You should go by the throw off on this one to identify who used it on their brand of drums. The B+B-like lugs are a copy of the Rogers used on non US drums and I've seen them on cheaper import snare drums as well. R. King a while back sent me a few of the lugs with the same middle knotch on your drum with the same question-Rogers? Nope.
This lug design wasn't patented so there was nobody to go after and nothing to be said. The Rogers beavertail lug was patented and we don't see copies of those. Mr. Grossman or CBS would of attacked if they saw that copied. Joe too...lol!
Further on the topic of the metal shell...Rogers in the 1940s NJ Farmingdale had a flat shell R faced lug 6 lug snare they named the Utility model. Then in around 1954 in OH there were a few uncataloged metal shell snare drums with the internal paper tag that reads Special Model. There are only 4 known of those that have surfaced so far. These have a flat shell as well. Then we had to wait a few years until the first early, also flat metal shell exterior, Rogers snare drums named the Holiday Model and Dynasonic Model. Even after all those flat metal shell snares there was a bead around the drum but it was an inny not an outy ridge/groove.