Think about it... Slingerland did not have separate molds to turn out shells with and without a wrap. Wraps of the time were thinner than they are now. I just removed all the original Red Glass Glitter from my 1965 shells and it is so much thinner that what is available today, or for the last few decades! Gretsch's shells were notoriously not undersized from the start. Add a wrap, and now you have a shell that is extremely difficult to get heads on and off! Today's cure for these Gretsch shells? Remo Classic Fit heads!!-Mark
Good to have that cleared up because I had understood that the natural shells were the same overall diameter and the finished dimension of the wrapped drums. I would have expected that not to be the case with say, Rogers, because they bought their shells from outside suppliers. But you also see very few Rogers drum in a natural finish. As noted above, Ludwig and I believe Slingerland were building shells in house and might have done something different depending on the outer finish.
So I try to stash this correct information in place of the incorrect.