Mike Spinetti has the Union Plaza 80 dollar chip overstamped No Cash Value on ebay. This must have been a tournament buy-in chip or something similar. I don't recall any others marked $80.

http://www.ebay.com/itm/80-UNION-PLAZA-CASINO-PAN-TOURNAMENT-NCV-CHIP-LAS-VEGAS-NEVADA-1980S-/271132135071?pt=LH_DefaultDomain_0&hash=item3f20bc0e9f