Old West Sourcebooks?

[Dunadin777]

I'm thinking of doing a special campaign sometime in the future set in the Wild West. Specifically, I'm looking at doing something within a few years of the end of the American Civil War. I know there's a GURPS Old West book for 3e, but I'm wondering how useful that will be for making a campaign in 4e--whether it retains its value as a guide for creating a setting in the current edition, and so on.

Some other sourcebooks I'm looking at right now...
Knuckleduster's Firearms shop and Cowtown Creator: I'm certainly going to be picking up Cowtown Creator, but I'm not too sure about the Firearms Shop. It says it contains 80 period weapons with a detailed treatment and some interviews with police with gunfight experience. I'm not sure how this might compare with the information already presented in High-Tech and other supplements.
Precis Intermedia's Shady Gulch Revisited: I've heard of this being another useful setting book, with a detailed treatment of one specific town.

Do any of you have these books? What's your input on how useful they will be? Any other suggestions for books would be appreciated, particularly if they won't require much translating from other systems(generic stuff would be great).