Okay, so we should be calling them 'manufactured after the casino closed' rather than counterfeits For detailed info see the article:
http://www.marlowcasinochips.com/links/davidspragg/osborne/osborne.htm

Shipping is $2 first chip and 50c per extra.

The 3 incused chips on row 2 are genuine. All the others shown were made for Carl Osborne. The genuine $100 SilverBird is relatively scarce untrimmed (many went in belt buckles, bolos etc.)