Well, my drum is definitely from the early 70s (Dec.9, 1971), has the "modified" B/O badge and, upon further inspection with my one functioning eye (sorry about that!), I did discover a "B" stamped on the shell right behind the round dial muffler. I tried to take a pic of the "B" but I can't get a clear one. I can assure you that it's there though.What I'm still not sure of is whether the "non-brass" rims on this drum are the originals. I would think that a Supraphonic with a brass shell would have also come with brass rims. Am I mistaken?
That's great information! It was always assumed that the COB 70's Supras were early 70's, but then some information surfaced that they were only from the late 70's. Your drum proves that they were indeed around in 1971. This makes me suspect they were made throughout the entire decade.
Thanks,
Bill