why is that interesting? That's where the gun was made. They are not Swiss pistols, they were made in West Germany.
Remember the time frame here. Late 70s. I bought my BDA in 1980 (for $369+tax) brand new and the store threw in two boxes of Federal 185gr JHP ammo (GREAT STUFF!!)
At the time, Swiss law prevented export of SIG (Swiss) arms. SIG went into partnership with JP Saur & Sohn of W.Germany, creating SIG-SAUER. The Swiss (SIG) provided the designs, tooling and some expertise, the guns were made in W.Germany and so could be exported around the world, not being a violation of Swiss law. (That law has since changed).
Browning bought about 5,000 some odd .45acps, a couple thousand 9mms and a few hundred .38 Supers, had their name put on them, and imported them into the US for sale. They are early model Sig P220s, but are not marked as such. They are marked "SIG-Sauer System made in W.Germany" and "Browning Arms Co Morgan Utah & Montreal P.Q.
The plastic grips have "Browning" on them, the wood grips do not. There is no model name or number marked on my pistol.