"Then how come cheques from the Shenandoah and Jockey Club aren't classified as "counterfeit"?? Is there just an inconsistency in terminology?"

There is a big difference in these and the ones you are asking about. The Shenandoah and Jockey Club chips were made for a casino that did not open.

Carl Osborne had the following counterfits made after the casinos closed. They were made to fool the hobby.
Bingo Palace - 100 N1363
Castaways - 100 N0874 & N1444; 500 N1445; Sports Book Oversized
500 N1436; 1000 N1437
Holiday International - 25 N6139; 100 N1056; 500 N1054
Park Tahoe - 100 N5448; 500 N5449
Rendezvous - 100 V6844
Sahara Tahoe - 100 N5513; 500 N5514; 1000 N5511
Silver Bird - 100 N0877, N9081; 500 N0870; 1000 N0869
The Treasury - 100 N2264
Eddie's Fab 50's, Reno N7126 $100; N7127 $500
Marina, Las Vegas N7167 $25; N1284 $100; N7168 $500
Del Webb's Mint, Las Vegas N7173 $100; N7174 $500
Del Webb's Mint, Las Vegas $5 & $25 H&C – CJ are real.