[the old trapper]

This beauty came from and old torn down jail house in South Central Texas!
Barrel length is 5 & 1/2", 38 cal.,Stamped top of frame 'U. S. Revolver Co. Made in The USA. ,5 shot, free spin cyclinder,# 20825 on trigger guard.No other markings , and did not remove left or right gripes.Took it to Cabelas and stumped him, He said not Iver Johnson, but thought it was interesting. any info is appreciated. Three pictures attached.
Tom