There are pics in the Complete Indiana Jones book...or whatever it's called. Haven't gotten around to picking it up yet, but flipped through it once at the book store. There's a pic along with a "call sheet" for how many blanks, dummy rounds, etc are required.
I'm thinking Indy carried the John Ingliss Co. BHP (made in Canada). It had black plastic stocks. The pictures in "IndyGear Main" show Inglisses.
I saw the picture in the book, I think it was an FN. If someone knows better, please chime in.