The bearing edge is good on both sides of these. Oddball I can't really see your blue oyster shell interior to see if it is the same shade as mine.

You all have eased my concern though of these not being authentic. As you say "they are drums, hit them". I didn't buy them to be in a museum but would like to know that I purchased authentic vintage gear.

Those aren`t mine, I found that kit on the net that authenticated them as original. They only say seventies but I think the last of these got the flat interior.