Yea... pet store people aren't very smart I've noticed.
I have about half and half rex and smooth coated, and none of the snakes care. As long as it smells like a rat, looks like a rat, moves like a rat (or not LOL), they eat em.
The only snake I own that is picky is my spider BP, she only takes ASF now, but thats okay because I raise those too.
Good. Then I can work with rexes and not worry. Glad snakes aren't THAT picky. Lol.