I think it was one of these...or maybe a Westward Ho .50.

My first visit to Las Vegas was in 1981. I liked the chips, and wanted to save some, but thought "that would be like sticking money in your pocket as a souvenir. Who would do that?" So I saved 3-4 fractionals...threw them in a drawer, and forgot about them for over a decade! In the early 1990's we started collecting ashtrays...which led to postcards...followed soon thereafter by chips, matches, dice, glassware, china, napkins, banks, and a whole bunch of other stuff!