Frank Sr was made in 1983, while the Hoffa hit occurred 8 years earler.

So it seems that by the mid 1970s Frank Sr was still rising withing the Chicago mob under his territoral boss at the time, Turk Torello. So it is possible that Frank allegedly acted as some type of messenger for the Outfit (many Chi guys both Ital and non-Ital went back and forth around the country at the time) and he became a "player" sometime around 1976/77 when Torellos underling and Frank's close associate Angelo LaPietra became the new boss in Chinatown...I think Detriot received the ok from Chicago and New York, and later they simply had to receive a report on how the job was done and so they sent some of the lower level "bagmen" or messengers, obviously because the bosses where still on the governments radar at the time or the heat was on...just my two cents