I have limited info on manufacture date and market value on supposed rare iver johnson .44, it is a 5 shot revolver, 2-1/2" octagon barrel, american bulldog stamped in top strap [1st edition?], cyl. bore checked out @ .462, how do you determine if webley? does webley make more or less collectable? revolver has 95% nickel intact, excellent grips and in fine working condition.