Farmall Cub

If a cub came originally w/ no lights, what was put in the holes for the light supports?

I don't know, but I would guess nothing or possibly corks.

Mud dauber nests.

A stock hood was used, holes were not plugged, the light post was simply left off. More than likely IH had a simple reason behind this...so that a bare bones cub could be upgraded with lights by the owner if desired at anytime in the future. The associated knockouts in the dash panel were also left in place.

Those holes were filled with NOS air.