Total speculation on this, but I'll toss it out anyway.

AC Sands and other casinos that offered Baccarat produced $20 yellow chips as a higher minimum bet than other table games. Same as in a lot of Nevada casinos (that I'm more familiar with). Why $20? Well the 5% commission on a winning Banker bet is a convenient $1 per $20 ($20 x 5%). No news there.

Typically, big-table Baccarat games use lammers to track commissions due from each player, with a settle-up period after each shoe. But the amount due, or change owed back for commissions can be any whole-dollar amount. Though it seems that AC Sands would have simply used their rack $1 chips, not a special one marked "Baccarat".

A totally speculative possibility -- perhaps it was a prototype or idea to more finely account for the gross handle and/or hold on the Baccarat game, if the Baccarat pit was a separate cost-center / profit-center within the casino?

Seems far-fetched, and even if that was the original concept behind this special $1 chip, it never made it past the discussion & prototype stage? Otherwise, I have no idea.