Upon closer inspection of the interior, there is a second, diagonal seam that is 180 degrees from the straight seam. I also do not see any digits inside the shell. All the lugs appear to be the same. The bearing edge has more of a rounded over style.

In the end, it will make a great rewrapped Teardrop FT. The leg brackets were not even made until 1970. So if the drum is original, which it sounds now like it is, it's post 1970 and not up to 75. They are in big demand in europe.