I was a boy back in the 1950s and went into town often to watch Roy Rogers movies. I found a DVD at my public library with five old, B&W Roy Rogers movies, this is the second one I watched, running under an hour.
The hook here is that Roy Rogers is a spitting image of Billy the Kid. Roy is riding west to try to find some work, the first place he stops he is mistaken for the outlaw. He is brought in, everyone thinks he is the outlaw, until he plays the guitar and sings a song. Then everyone says "We know for a fact that Billy the Kid can't sing or play music." So Roy manages to get a temporary assignment helping Sheriff Pat Garrett.
The story here is settlers from out East are having a hard time because of the cattle ranchers' meddling. They have to plow their land but the horses get stolen. Charging them locally wouldn't do any good, their friends on a jury would just acquit them. So Rogers and Garrett hatch a plan to have the US Cavalry catch the men with stolen US horses, that would require them to be in a federal trial.
As with most (or all) Roy Rogers movies he does some singing and he of course had a great, melodic baritone voice, as good a singer as any in those days. And he did find a girl to get sweet on him.