Wow-that's enough to drive anyone nuts and give any authenticator a stroke....BUT, before you flip out (and I give up authenticating) know that there was absolutely positively an earlier version of that shoe with a stamped insole. So, no, there should not be variance on the same style but I'm pretty sure that Prada just changed the specs on the later production. Seeing the fabric label really threw me too. I just looked again and not only does everything look clean and correct but that shoe was a bear to make and if it was knocked there's no way it could be that clean and lined in leather. You may want to contact the company to verify what I've posted and I'm shooting myself for not buying them as there were two pair at the outlet over a year ago in my size and they were $150-runway samples. They are beautiful!
Remember too that yours are preowned from the minimal wear on the sole so that means that they most likely were from that earlier group.