This seems to have been made immediately after the "SGT Bilko" show went off the air, as a vehicle for Phil Silvers by Nat Hiken, the mind behind "SGT Bilko." It may have started out as a pilot for a new show starring Silvers. If so, it is not surprising that it was never made. Silvers' character as a fast-talking con-man does not merge well into the western genre.
It is always good to see Silvers in anything, but he's not very convincing as a cowboy, even "the slowest gun in the west." There are some funny moments, but many of the jokes fall flat. The theme-song, a western-style ballad about the Silver Dollar Kid (Silvers' character), is repeated far too many times, far too loudly, and gets intrusive after a while. The rest of the cast is stiff, and do not seem to be very well-rehearsed.
The movie picks up when Jack Benny's character appears. Benny was rather famously not very good in movies, but he is very natural in this role -- which is just an extension of his character from radio and TV. Unfortunately he isn't in the movie very much, and the climax of the movie is a big letdown.
It might be fun to see for fans of Silvers or Benny, but don't expect big laughs.