I quote from our Canadian Whisky.com Expert (who is likely enjoying a long holiday...)
"Schenley is still made today and goes for around 24.00 USD. It still wins gold medals and why? Because the flavor speaks for itself. Strong and rich with flavor and a kick but no strong after taste. Now to price if you find an interested buyer you might get double the retail. However as it doesnt get any better or age in the bottle you have a choice. A gift to a friend or maybe even have a get together open the bottle and share."
Also to note that since the whisky does not age in the bottle - even though it's dated 1980, what you have is still an 8 year old scotch. Actually older bottles have an 8 year old statement on the label and newer bottles do not. Does your bottle have this statement?