I'm looking at sights for my Model 3B. Apparently a Weaver #2 base (part 48402) and a Weaver Side Mount with 1" rings (part 49350) are supposed to fit on the Model 5 and probably other models of this vintage. The dealer had the ring mount (C$31) but did not have the base in stock (on order) so can't yet verify a fit. Mine has two holes - 2 3/8" on center - for the base mount and also a notched out spot at the very end of the breech for a peep sight (one hole). Apparently a Lyman 55 peep sight was used, but the dealer says he doubts these are available any longer.