No, the mark in the circle is correct for that era.
My Miroku / Browning side-by-side is marked BB2 in a circle just like that, for the year after, 1976.
The first letter is the year letter, and the second just signified Birmingham. The number relates to its owner working at the Proof House, so not the most senior chap, but his number two.
By the by, my Miroku is stamped "Made in Japan and assembled in Korea". I didn't realise they did that.
HB
Miroku started having those guns assembled in Korea in the later years of BSS production. Some people seem to think that the guns assembled in Korea are of inferior quality and won't buy one that was assembled in Korea. I have no idea whether there's any real difference. After all, there was a time when we couldn't have imagined buying a car made in Korea. But they're now quite common. For that matter, who could have imagined buying a shotgun made in Japan before Winchester introduced the 101?
