Pardon a pretty ignorant question. From what I understand, Gretsch USA customs haven't always gone by that name exactly. What names has their top of the line, iconic, 6 ply drum sold under through the years? I realize my question assumes that it's always had the same number of plies, same hoops, same wood combos, etc. etc. But if certain specs have changed on their top of the line model, I'd want to know that too. How different is, say, a 1960s kit to today's? Thanks!