From my understanding pet stores are a place to dump offspring you dont want, meaning you probably have a small time breeder near you or someone who bought a snake and ended up regretting the decision and dumped it there.

I'd talk to the people there and find out about it. You could probably find the breeder or figure out how they got it. And I'd totally suggest getting them if you have the cash, its always nice to add some pretty pastels to your collection.