The Consumer Product Safety Commission was established under Public Law 92-573; 86 Stat. 1207, Oct. 27, 1972. I believe safety matches were one of the first products regulated. Here is a summary of current requirements. Latest revision 2003.

TITLE 16--COMMERCIAL PRACTICES

CHAPTER II--CONSUMER PRODUCT SAFETY COMMISSION

PART 1202--SAFETY STANDARD FOR MATCHBOOKS--Table of Contents

Sec. 1202.4 Matchbook general requirements.

A matchbook shall meet the following general requirements:

(a) The friction shall be located on the outside back cover near the
bottom of the matchbook.

(b) The cover shall remain closed without external force.

(c) No friction material shall be located on the inside of the cover
where possible contact with the matchheads may occur during ordinary
use.

(d) There shall be no bridge(s) or broken bridge(s).

(e) No matchhead in the matchbook shall be split, chipped, cracked,
or crumbled.

(f) No portion of any matchhead shall be outside the matchbook cover
when the cover is closed.

(g) No part of a staple or other assembly device for securing the
cover and combs shall be within or touching the friction area.

(h) A staple used as an assembly device for securing the cover and
combs shall be fully clinched so that the ends are flattened or turned
into the cover.

Here's the section that covers the transition from front striker to back striker:

TITLE 16--COMMERCIAL PRACTICES

CHAPTER II--CONSUMER PRODUCT SAFETY COMMISSION

PART 1202--SAFETY STANDARD FOR MATCHBOOKS--Table of Contents

Sec. 1202.7 Prohibited stockpiling.

Section 9(d)(2) of the Consumer Product Safety Act (15 U.S.C.
2058(d)(2)) authorizes the Commission to prohibit manufacturers and
importers from stockpiling a product subject to a consumer product
safety standard between its date of issuance and its effective date. A
manufacturer or importer is in violation of Section 9(d)(2) and of this

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section if it fails to comply with the following:

(a) Definitions. (1) Base period means, at the option of the
manufacturer or importer concerned, any period of 365 consecutive days
beginning on or after January 1, 1973, and ending on or before December
31, 1975.

(2) Rate of production (or importation) means the total number of
matchbooks manufactured (or imported) during a stated time period. In
determining whether a matchbook was manufactured during a stated time
period, the date on which the cover and combs were assembled to form a
matchbook shall be used. In the event that a manufacturer currently
operates a matchbook manufacturing plant that it did not operate during
the base period, or that it did not operate for an entire base period,
that manufacturer shall use, as the rate of production during the base
period for that plant, either (i) the average daily rate of production
(including nonproduction days such as Sundays, holidays, and vacations)
for the part of the base period he did operate that plant, multiplied by
365 or (ii) the rate of production during the base period of his most
nearly similar matchbook manufacturing plant.

(b) Prohibited act. Manufacturers and importers of matchbooks, as
these products are defined in Sec. 1202.3(i), shall not manufacture or
import matchbooks that do not comply with the requirements of this part
between the date that this part is issued and the date that it becomes
effective at a rate that is greater than the rate of production or
importation during the base period plus 15 percent of that rate.

(c) Documentation. Manufacturers and importers shall maintain, for a
period of six (6) months after the effective date specified in
Sec. 1202.1(b), appropriate documentation to be able to substantiate to
the Commission that they are in compliance with the provisions of this
section.

And section 2058 portion that discusses timing:

(g) Effective date of rule or standard; stockpiling of product
(1) Each consumer product safety rule shall specify the date such rule is to take effect not exceeding 180 days from the date promulgated, unless the Commission finds, for good cause shown, that a later effective date is in the public interest and publishes its reasons for such finding. The effective date of a consumer product safety standard under this chapter shall be set at a date at least 30 days after the date of promulgation unless the Commission for good cause shown determines that an earlier effective date is in the public interest. In no case may the effective date be set at a date which is earlier than the date of promulgation. A consumer product safety standard shall be applicable only to consumer products manufactured after the effective date.
(2) The Commission may by rule prohibit a manufacturer of a consumer product from stockpiling any product to which a consumer product safety rule applies, so as to prevent such manufacturer from circumventing the purpose of such consumer product safety rule. For purposes of this paragraph, the term "stockpiling" means manufacturing or importing a product between the date of promulgation of such consumer product safety rule and its effective date at a rate which is significantly greater (as determined under the rule under this paragraph) than the rate at which such product was produced or imported during a base period (prescribed in the rule under this paragraph) ending before the date of promulgation of the consumer product safety rule.

You can see why the date cannot be precise, as manufacturers were allowed to stockpile quite a lot of the old front strikers. There's also no rule I can find that controls matchbooks already delivered to the customer. I use 1972 and an approximate date, but casinos could have used old matches for several more years if they had them in house.