Since I too have a 53 and this question has been one on my list for my restoration too. I am 75% sure the bolt heads were natural, it would of taken an extra step in the manufacturing process to paint them. I'm thinking the assembly line back then was into getting those trucks put together as cheaply as possible. Only other thing that could make me change my thoughts on this is if the bumper and brackets were assembled in advance and then painted in which case the brackets would have gray overspray on them. Were the bumpers and brackets assembled then installed on the vehicle? I'm thinking so. This could be the case. Why we are at it, were the back sides of the bumpers painted too?

Last edited by sstock; 09/01/2014 3:37 PM.
1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration