To settle this, I went to the POCA Archives and pulled up all 3 of the factory's Official Illustrated Parts Catalogues. The earliest was printed in April 1972 (blue cover). The Catalogue most everyone has was printed in April 1975 (orange cover). As it turns out, everyone is correct, sort of- from the pilot bushing/bearing part numbers listed.
DeTomaso lists a pilot bearing part number for the first cars- possibly the 285 pushbuttons since it also lists a half-dozen early ZF serial numbers that definitely got bearings (the factory called them roller bearings) which Mangustas also used in an extension housing. Pantera serial production supposedly started Jan 1972.
Sometime prior to early '72 (blue cover parts catalogue) , they began listing a bronze bushing as well. All three Catalogues show both part numbers and I don't know of an earlier published factory parts list. So early '71s got bearings (as well as Mangusta gearboxes & 2 hole adapter bell housings) and after that, Ford- DeTomaso could have used either with the later 5DS-25/2 ZFs, all the way to 1987. I'd love to hear from other researchers on this subject.