Here's a denim shirt:
Forget that it's a particularly ugly shirt, there's a few problems with it:
1. RRL is pretty fond of using, and mentioning that they use, high rim japanese pearl snaps. These aren't them.
2. I've never seen it before. Unless vintage (which this is not as indicated by the tags) it's rare to see only one seller selling a style of shirt
3. coming from someone who has alot of RRL denim shirts, I don't own or have seen any RRL denim shirt with a snap button at the collar. They always have a regular button or star button, but never snap (levis, lee, and wrangler, yes, but not RRL)
4. Vintage or new, RRL denim shirts tend to be selvedge
5. I do not own and have never seen a RRL denim shirt with two snap buttons at cuff. Jcrew does this, but RRL always has the traditional three snap buttons at cuff
All of these apply to denim western shirts (not work shirts) which the shirt above clearly falls in the category of. From the very latest denim western to the older and vintage ones currently on ebay, all of them adhere to points above. I could be wrong, of course, but I don't know.....