I noticed this same thing on a VERY good Ronald Reagan western. The first Ronald Reagan film I ever got to watch was: "The Last Outpost." I accidently found it on DvD under the title of: "Cavalry Charge." I think "The Last Outpost" sounds as a better name for this fine film.
Anyway, this movie also stars: Bruce Bennett as his older brother and who is a Colonel in the Yankee Cavalry. Reagan's character is a Captain in the Confederate Cavalry. This movie also has Noah Beery Jr in it as a Confederate Sergeant. I forget who else is in this movie.
