Yea, she looks pure pit to me too.
Even if she was the runt, I don't think she should be so small. 15lbs at 16 weeks. We were also told she was paper trained. She wasn't. I have also noticed that the SPCA here labels all pits as amstaff's. red-nose is always pit, right? So her previous owner could have been misled, or we could have been. Anyway, pretty much everything we were told, seems to be inacurate.