Just had pictures sent to me regarding a 1943 Long Branch, on the left side of the receiver it is stamped RB 11/46....
I was told it went to BSA for repairs and upon completion was stamped. Is this info correct and what does the RB stand for? It has a beautiful 2 groove barrel and was told it has a BSA marked buttstock.
I believe that you have stumbled upon an early FTR Long Branch.
If you examine the markings closely you will probably discover that it is R "LB" 11/46 (ie. Repaired Long Branch November 1946).
This system of markings seems to have been discontinued before 1949.