I would say that most if not all of the people who were around in 1966 and were actually old enough to a) know what was going to happen and b) who were financially capable of socking away a ton of money, are likely at this point deceased being 75 or older (assuming an age of 25 @ 1966).
they most likely sold in the early 80's.
I don't think many people are sitting on hoards that have been in the closet for the past 50 years. These hoards would have been sold or divided between the heirs over the last few decades.