I remember this film from when I was a young boy and it was rerun on television. Everything was black and white in those days. I really enjoyed seeing it again for nostalgic reasons.
Another reviewer commented that there were several almost homo-erotic scenes in the film. If they were meant to be viewed as such, it never occurred to me as a kid; I just saw it as people becoming pals. I still look at it that way. I hope that is how it was meant. Movies back then reflected the morales of the time, so I think that is how those scenes were intended, innocent.
SPOILER
The ending to the film, while historically impossible, is clever. It offers a funny suggestion that Billy the Kid really did live on, that Garrett did not in fact kill him. I like the ending as I thought it was pretty clever. Besides being historically inaccurate and impossible, that trick was not likely to have happened like that, in my opinion. If Garrett had indeed "removed the firing pins" from Doc's guns, he would almost certainly have recognized that he had wound up with them, unless Doc and Billy used the same weapons, and possibly even then.
On the other hand, he might not have noticed he got the dead weapons since he would have been focused on Billy the Kid, to see if he were aware of the switch.

Made Jane Russel the spokeswoman for the Cross Your Heart Platex Bra. She hawked those bras for many years on TV. Movie was OK for the era, but came out a comedy instead of a drama.

This is an odd western filled with melodramatic winks, glares, and other assorted facial contortions to try and buoy the meandering script. Jack Buetel plays Billy the Kid, ricocheting back and forth between being an earnest young man, a mysterious gunslinger, and a smoldering homo-erotic male model.
There's several awkwardly intimate moments between Billy and the older shootists.Then enters.......the babe.
Howard Hughes not only gave Jane Russell her big break in this movie, he also attempted to give her bigger everything: he invented and engineered a bra that thrust Russell's assets into the spotlight. And apparently right into the faces of Hollywood's moral code censors, who ordered about 30 seconds of perky mammalian glory cut out forever.The film doesn't know if it's a macho cowboy sausage fest, a comedy, or a romance.
But that's what makes it so dumb and horrible and interesting.
It staggers around in an entertaining and strangely compelling way.If you understand and enjoy the beauty of a truly bad movie-- as long as it's great....
Then let your eyeballs take a look.
This is a pretty good terrible film.

Billy the Kidd was killed in New Mexico in July 1881. Doc Holliday was in Tombstone, AZ with the Earps from September 1880 thru October 1881 when the Gunfight at OK corral
occurred. Prior to that he was in Kansas. He could not have had anything to do with Pat Garrett as Sheriff of Lincoln County and Billy the Kidd during the Lincoln County War. There is no record to show that any of these men ever even met.