From what i remember the T5 was for export to germany,
As all late 65 and later Dearborn and Metuchen built cars usually have a body buck tag on the inner right or left fender or beside the cowl under the right fender on 71-73 Dearborn Mustangs, the buck tag is one of the best items to start identification of a real T5, however also here inconsistencies have been found.
64 1/2 through 66 T5s are tagged with an X (for export) only on the body tag, 67- 68 T5s have a tag with "X W. GERMNY T5", on 70s to 74s a "T5" or also a "X T5 W Germny" was found on their ID tags or buck tag.
Looks like you got a rare car there jason,
Hope this helps.