Can it be? Yes, but not with any of the ambi-safeties made for the 1911 or copies. The B-M safety works differently. It does not block the sear like the 1911 safety does, it cams back the hammer and blocks it directly. In other words, the internal operation is different; a 1911 type safety won't work and can't feasibly be altered to work.
AFAIK, there is no ambi safety made for the B-M and I doubt the demand is there for anyone to make one.
(Don't confuse the B-M with the Argentine-made licensed Colt copies. Those are identical to the M1911A1 and all parts interchange, so an ambi safety made for the 1911 will work fine.)
Jim
