Scott,
Barbados redfoots do not get to be particularly large. In fact, the adults I have seen in the past were rather smallish in size.
The origin of them was thought to be from Caribe or other Indians who carried them from northern South America. However, the more likely idea is that Europeans are responsible.
Salespeople like to mix locality names, colors, etc. almost at random. The larger Red-foots seem to come from Paraguay and Bolivia, so it MIGHT be a Bolivian 'Giant'. If the plastron is mostly dark, this is a possibility.
I had a pair from Barbados about 5 years ago that were probably 10-12" SCL and 1800-2000grams. So not large at all. I wish I could find the pics I have of them.