[Based on the experience of a friend who reconditioned and repaired these by the van load in London, during the early 70's or late 60's.]
It would appear that FN sold these throughout Europe on an agreement with Browning. Apparently some were even manufactured for the Middle-Eastern market, as they were lettered mostly in Arabic. I would think they "came home" with someone as I doubt Browning wanted the potential sales competition.Of the few I've seen, that's how they got here.
Jim