Memory jogger>>>>>Shims/spacers for:, door latch, radiator, seat mounts, hood, body or bed mounts, shocks, springs, bumper, tail lights, tailgate/chains, steering column, hinges, sun visors, spare tire stuff, suspension, gas tank, exhaust, headlights, emblems, vents, linkage, dash component, wipers, window or windshield mechanism, horn ... look around for something on either side of truck with that hole pattern. Because there are two, could be left side, right side. Can't be that many places with a hole pattern like that. Unless they are from your lawn mower!
The sharp, stick up edge also leads me to think holding/clamping something down tight, like rubber, material or maybe metal. I don't know 40's trucks though. I know I have seen that piece on TF trucks I've had but can't remember and don't have any now. I keep thinking door latch/catch or tailgate catch? Barn door catch on Panels/Burbs? Lift gate catch? But there are no wear marks so probably not that category. The big holes, if they are for bolts, are for a major strength item. Clearance hole for TWO! 3/8 bolts.
