I'm ready to take custom orders for occupation-related small dogs' costumes. Sorry, no military, but I'll gladly sew nurse's, chef's, judge's, mock dress shirt & tie for the distinguished canine, policeman's, etc. Here's one of three in my Shop that are perfect for your pint-sized cowpoke:
https://www.etsy.com/listing/99340503/western-dog-shirt-stonewashed-jeans-one