First, I just wanted to let you know that boas are live bearers, no eggs so no hatchlings, they're called neonates or newborns. This is just an FYI in case you decide to try to sell them so you don't use the term hatchling.
If they are truly intergrades of common boas (also known as Colombian or common redtails - Boa constrictor imperator) and true redtails (several localities of the true redtails - Boa constrictor constrictor), they aren't unheard of. The true redtails aren't as common as the Colombian or Central American cousins, but they aren't what I'd actually classify as rare. It is rather frowned upon to mix the two except in the case of some of the color/pattern morphs - a whole other topic. Even so, crosses between any of the boa constrictors (Colombian, Central American & true redtails) isn't unheard of - it's even supposed that some so-called pure animals may actually have some cross blood in them because of the sketchy collection data on imports. My guess would be that they are probably just nicely colored common/Colombian boas though there may well be a chance there is some true redtail blood in them. Either way, they'll make a nice pet boa. They could be used in a breeding project, but it would be best if selling them to represent them as either crosses or unknown heritage.
Hope this helps.
Raven