I don't know when they started, but Keller shells are stamped on the inside..

Ludlover, perhaps you could visit www.kelleratthecore.com and contact them directly.

It's VERY likely they are Keller shells. There aren't that many manufacturers set up to make bass drum sized, ply shells. Who else could it be besides Keller? As far as the ply count....yes they can be counted by taking the head off and looking at the bearing edge.

Thanks, I called (Keller) and a human actually answered. The man said that Keller has always stamped the date on the bearing edge of the drum. The only way that they won't have a date is if a distributer or private owner has cut the drum down and took the stamp with it.

Good to know. Thanks

The shells are very bad condition all i can say is water water on the shells, set was a 22'13.16. and 14 snare..shells are very bad,but if you like when i get to them i will email you some photos and you can have the shells for the shipping.....In all the drums i just got have a 38 sets MIJ, and not one 14" floor tom ..most sets are 4 pc with some being 5 pc also...Mikey

The guy sold the drums before I could go look at them this weekend. First come first serve in this situation. I was going to buy them too. But the good news is that I found a vintage Slingerland set that I am very interested in. Maybe it was meant to be. I started a post about them in the Is this a good deal? - How Much is it Worth? section. It is titled Slingerland and Ludwig if anyone wants to take a look.