"I have been a wheel gun man for a long while"
Welcome to the Forum,
The above statement may change if you decide to start shooting those pistols, especially the 645.
The 645 is not rare, but they have become difficult to locate, especially in the box with all contents. There are many threads here on this model and they are a pleasure to shoot. They are almost never seen in my parts, and if you can find one it's going to be pricey. I believe the same can be said for you folks in the U.S. I own one with adjustable sights and wouldn't part with it. I can't comment on the Model 39 as I don't own one, but someone will be along shortly to help you out.