Synchronixe

So I have had a desert tortoise for about 5 or 6 years and i'm just now starting to realize how lucky I am. I rescued it from a woman in a local nursing home that could no longer take care of it. I was told it was a sulcata but after a few years of having it it didn't grow very much like a sulcata would, so i was suspicious. I did some research and found out that it's indeed a desert tortoise. Not sure if sonoran or mojave, but if anybody knows anything bout them and what they're worth i'd be very interested.