I know zip about wild bettas, but I would be very, very surprised if a commercial retailer crossed their stock with any wild species. Because of how bettas are bred there's no way it would be an accidental cross, and I honestly can't think of any reason why someone would create a wild crossbreed and then sell them as "just" a domestic.
The spots on her gills (and chin) that you mentioned are very common on domestic betta splendens, not every betta will have grayish-silver patches there but a lot do, no need for wild ancestry.
To my eye she looks like a very lovely VT female, congrats on getting her! :)