On Browning's web-site there's a parts list for the 1885; although Browning doesn't still make the 1885, this is a 2005 document (it's under the area for parts for current guns, not the one for obsolete). Anyway, that list notes parts that are interchangeable between the 1885 and B-78. It seems the extractor is NOT one of those parts (at least according to the list).
By the way, thanks Ranger for the manual. I have a B-78 and try to gather whatever info I can on them (which, as you may know, is pretty rare). You've provided a great service to us B-78 owners. Thanks again.