There are "Browning" 20 ga. A5's made earlier. During the WWII years they were made by Remington on the Browning patent. Made in USA, not in Belgium. I think their slang term is "American Browning." My guess is during the war, FN was kept busy making other stuff than quail guns.
This is all off the cuff. I haven't gotten mine out of the safe nor consulted a reference book. I think the serial numbers are on their website and in Blue Book of Gun Values.

If it weren't for the wonder of electricity, you'd be reading this post by candle light!