I was able to find out that Silver Heels was a jewelry store located in Montana, but has since closed. They do not have a website, making it especially difficult to find information!
From various sources, it sounds like they were a custom jewelry store that emphasized southwestern style jewery. Some Yelp reviews of the store indicated that they carrierd various types of Turquoise. Here is a picture of the store from Yelp- you can see the store’s sign to the far left of the building:
The store opened on 1972, so I would say that your piece was likely made sometime after that. Your cuff has a very 80’s look to it.
Not that this helps at all, but I was also able to find a ring for sale on eBay that was also engraved with “Silver Heels” on the back side.
You barely see the mark, but here is the back side:
