Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4677202.

This is a speader/support for the front of the bed of the 1/24th Testors Boyd's Hauler (aka Van Hauler) and Testors Custom Chevy C1500. Both kits have identical bodies and flaws. That being the warping of the rear fenders leading edge where it meets the cab (see pics). I've had several of these kits and they all suffered from the same problem.