806D

The original side emblems said "FARMALL" on Farmalls, and "INTERNATIONAL" on Internationals. There are other distinct differences:

Farmalls have adjustable axles in the rear.
Farmalls LOOK longer, taller, leaner. Farmalls have relatively high, narrow rear tires.
Farmalls often have square fenders over the rear wheels, but can also have "clamshell" fenders.
Farmalls have headlights on the sides of the hood, and/or on the fenders.

Internationals have fixed rear axles.
Internationals look shorter, lower, stouter.
Internationals have very low-looking, wide rear tires.
Internationals have round fenders that cover the rear wheels.
Internationals have headlights in the grill.

The serial tag will tell which one you have. A Farmall 806 is marked "F-806" the International is marked "I-806".

You can't believe the old farmer that tells you, "It was like that since it was new." 40 years does strange things to a person's memory. Plus, people don't always tell the truth.

There is one unlikely scenario in which the emblems would have been missing since the tractor was "new:" The clods that handled the tractor during shipment ruined the original sheet metal, and the replacement sheet metal didn't come with the emblems. In this case, you got boned by the dealer, who sold you damaged goods as new.