Cassandra nailed it. "Red-tail" is just a common name anyway and is generally ignored in the herp community. BCCs are most commonly referred to as "True Red-tailed" and BCI's are commonly referred to as...well..."Common", but pet stores will often refer to both of them as Red-tailed Boas.

There are seven sub-species and each species have different locales with different visual traits. To make matters worse, there are now a lot of hybrids in the pet trade to further blur the lines.

I usually just refer to mine as a Boa Constrictor or if I am speaking to someone in the know, I tell them I have a BCI.