i work at napa, besides the dust boot itself, im almost positive in the book will show more than one style seal with the exact ID/OD if measured by the spec of the original seal. some may have dust boots as pictured above. some have stop flanges so it can only press in to far. some has rubber style dust boots and some has none. only we cant predict where the seals are made from as some are made in china, japan, mexico, USA but comes in the same boxes.
if im correct, you guys are trying to figure out how to install this? i havent worked on a t5 at all but the last time i installed one of these on a different trans, i used a piece of exhuast pipe to slide inside the seal to the deepest/hard point and tap it in with a rubber hammer.