A lot of the confusion has to do with the way people use the common name "Red Tail Boa". Some folks (especially pet shops, who want to make their boas look like something special so they can sell lots of them for lots of money) call every single variety of Boa constrictor a "red tail". Others refer to Boa constrictor constrictor from South America into southern Central America (IIRC) as "true red tails", while Boa constrictor imperator from Central America gets called "BCI". Since the Central American BCI has been more common in the pet trade and easier to breed, that's what you'll find in more pet shops. (And what yours looks like)

~Bruce, who knows just enough about Boa constrictor localities and morphs to be very easily confused!