An APBT owner once told me that APBTs and AmStaffs are the same breed. I didn't know any better, so I looked it up, and came back to her and told her the differences. She said it didn't matter, they were so close they "might as well" be the same.
i know i would have a hard time telling a lot of the UKC show ring pit bulls from the AKC show ring amstaffs. it's a lot easier when you're talking working bred and ADBA