Colt called that gun the "New Army and Navy revolver" and it was officially adopted by both services. But that gun is a civilian model, not military, made (as SC says) in 1907. Colt sold its commercial guns as the "Army Model" and the "Navy Model", differing only in the grip design (most service revolvers had wood grips). That one is the "Army" version.
I can't read the initial stamped in the butt; they might add to the value.
Generally, those guns don't bring high dollars mostly because they are fragile and have a well deserved reputation for breaking parts and going out of time. Few parts are available and even fewer gunsmiths will work on them. Colt has no parts and won't even attempt to repair them. As is, that gun would probably bring about $200-250.
For grips, try http://www.gungrip.com/detail_G8__22__colt%20Grips.html
for good repros, but note that there is some variation in those guns in regard to butt length front to back. Check the picture closely but if the grips don't fit you can return them if you have not altered them.