Last night, while celebrating Xmas at my brother and sister in laws, they mentioned they had a bottle that my father in law received as a gift.

It was 12 year old Scotch.
Fred passed away in 1994.
He apparently received as a gift in about 1972.
It had markings from Scotland, where a daughter had bought it while a cruise/travel guide - from the late 1960's.

All told, the nearest we could estimate and search via markings, this was 45-50 years old.

I can tell you that it was remarkable...smooth as silk.