Mark Murphy, "The Baseball Card Kid", has been buying and selling vintage unopened material for about 20 years and has a strong positive reputation in that hobby segment. He originated the slabbing and grading of unopened packs and afiliated himself with the original GAI to provide that service. He's no longer selling unopened material, likely because a number of reputable (as well as non-reputable) competitors cut his margins too thin.
In any event there's plenty of unopened 1960s and 1970s stuff out there. Larry Fritsch Cards will still be selling 1975 Topps baseball Cellos when your Great Grandkids reach age 21 🙂 - that's how many cases he is purported to still have warehoused.
The biggest horde I have ever seen was at Mike Cramer's warehouses when he ran Pacific Trading Cards out of Edmunds, WA. Mike was one of the (few) steady buyers of bulk cases of Topps product starting in the 1960s - they had to buy 1 or more trailer truckloads each year from Topps without knowing what might be inside and with no haggling over price. I saw unopened cases of wax, etc dating back to the 1960s, and all sports (and non sports) covered, as recently as the early 1990s in Mike's warehouses. I'm sure Mike's either sold them off or put them into bonded, secure storage now.
