Yeah, I was in a conversation with a guy who claimed to be one of Buddy's "chart readers".... and that Buddy gifted him one of his kits and to tell an "actual" Buddy kit was he told them to remove the re-rings. I think the late(r) 3-plys were Maple/Poplar/Maple, so that would be stronger, but then again, alot of drummers are (shall we say) ignorant in the ways of drum making and drum building, so he might not have known that Ludwig changed their shell configuration in response to Marshall stacks.
Ludwig phased out the 3 ply shells at right around the same time as Buddy came back aboard. The 3 ply shell was made by taking a flat 3 ply board ( a layup consisting of a single fat ply of poplar sandwiched between two much thinner plies of mahogany and/or maple) and bending it into a cylinder with a wide scarf joint for the glue at the seam. The re-rings are pretty much a necessity for such a shell to hold it's shape as the board wants to go back to being flat. Around 1977-78 Ludwig adopted a six ply design that was similar to what Gretsch had been doing for about 20 years prior. Those shells were made in a completely different way with the individual thin plies being molded and glued together into a shell with staggered seams (instead of one big seam where all three plies met) and some plies with opposing grains. This type of construction will hold it's shape without re-rings and is what nearly all drum manufacturers use today.
While Buddy would certainly be worth doing some customizing for (and his tom holder seems to be just that sort of thing) the 3 ply shells simply would not work well without the re-rings (nor would have the shells of the Slingerlands and Rogers drums Buddy had used prior). Also it kind of defeats the purpose of having a major endorser if he is playing drums you don't actually sell. If word of that gets out it would be embarrassing to say the least. Ludwig did make a 4 ply shell in the early 80's that they called the Super Classic and they also lacked re-rings since they shared the same sort of staggered ply construction as the 6 ply models. I don't know if Buddy used any 4 ply sets but it's certainly possible, given the number of sets he seemed to use, whether his own touring sets or ones provided for TV shows and such. Either way it is correct that these drums lacked re-rings but I think your guy may have been confused as to the number of plies.
If anything I'd have expected Buddy to prefer having the re-rings that had featured prominently in all the shell designs of the drums he had been using since the 1930's (and went back to with his final set of Radio Kings). Other than Gretsch (which Buddy seems to have avoided using for some reason) that ringless design was somewhat newfangled technology for most American made drums at that time.