First, John Browning never designed that rifle. The gun was made by FN in Leige, Belgium and marked as such for sale everywhere but the U.S. In the U.S., Browning Arms Co. has a deal with FN to put the Browning name on arms made by FN whether Browning designs or not.
AFAIK, the difference in marking has little or no effect on the value - it is the same gun.
Sorry I can't help on the date of manufacture; if it is important, I would contact FN.