[drc]

I agree with Jim.

Terms like master set were invented after the T206s were made, so they aren't intrinsic to the cards. Just the way people define things. But traditionally a set (basic set) doesn't include errors and variations. Errors and variations are extras. Many sets are physically numbered on the backs so you know exactly what constitutes the basic set. Little more straight foreword than 1, 2, 3. Though there will be complications, such as when two players have the same number (54 Bowman Ted Williams)-- then there's a judgment call.

Most masters sets I've seen are for modern cards. Until now, I'd never really associated with Pre-War sets, no doubt mostly due to their rarity and difficulty.