The two-door, single-tank thing has happened a lot on the Early Broncos too. Ok, so not actually "a lot" and it's not on every one of course, as there are plenty with just one door. But several of the double-door owners were original purchasers too, and know that the dealer did not fudge anything at their end.
We've learned to figure lots of odd things happened to the semi-orphan Broncos of that time, and especially on stuff like this as it was literally the first (and only) year for any doors at all. With the pickups it was also a transition in that no more in-cab tanks were allowed on any model. I think there were some doors on some model trucks prior to '77, but not actually sure about that. Bill has answered that before, but I don't remember the whole transition thing between surface mount, recessed mount, door type, and the various combinations thereof on the full-size trucks.

Doesn't seem too surprising to me then.

Paul

 

1973/76 F100/350 Styleside mid-ship/aft axle tanks have exposed fuel caps, 1977/79's have fuel doors.

D4LY-65405A26-A = The fuel door w/hinge is the same: 1974/76 Lincoln Continental Mark IV; 1977/79 Lincoln Continental Mark V & F100/350; 1978/79 Bronco.

On the 1973/76's with exposed caps, some of the quarter panels came with two openings, even if there was only one tank.

A painted metal cover (D3TZ-9080-A) was installed in the hole in the quarter panel if there was no tank.

 

Well, good deal..... I sure am glad to know that other trucks (and Broncos) have the same anomaly as I have.
AND... good to know it came from the factory that way. Maybe that gave the owner the option to have a second tank added if he wanted (??).
(This owner might just do that very thing.)

Thanks everyone.

Mike