Maybe the people you were talking to were thinking of the full-size trucks. Specifically the F250's, which did go through some major driveline, accessory and regulation changes mid-way through '77. Leading to the whole "mine's a '77.5 F250" thing.
Two of those changes actually made it to our Broncos. One was removing all the gas from inside the cabin by moving the charcoal canister/evap system completely outside, and the other was the addition of gas doors.
Presumably yours has gas doors to prove to the non-believers that it's a '77?
Unlike many of these changes, where the manufacturer makes the early running change, but didn't implement them under the old year designation and just sold them as the next year model, these got the '77 registration, but the '78 changes. Not sure just what month got the change-over, but it's listed in the books. Usually by serial number at least, if not month also.
And of course you're absolutely correct that all '77 Broncos were Early Broncos (or at parts stores: "is that a small Bronco?") and in '78 they were "full-size Broncos" only.
Not sure if Ford or the various DMV's also listed them as '77 1/2 trucks, but we did out here in the world.
A friend of mine had one of the later ones. I'll have to see if he remembers the registration indicating anything specific.
Paul
