Stalks look very close to late 30s-40 International PU which mount vertically? 38 Ford beer barrel mounted similar The Guide T-3 sealed beam lamps may not be original, is there anything else under the dirt that may assist.Very feint however I see Sealed Beam and Guide, is there Made in USA or anything else, part #?
Several big trucks used heavy cast brackets to mount the headlights. Auto-car, Brockway, White, Reo, and others.