Mark,What Bob said and to add a little
My 51 Subn came with its stainless grill and bumpers.but its an early 51 with a low serial#
As far as I know the 52 model year started the War crunch so to speak
The only "Brite work" so to speak on my 52 1ton is the Windshield divider,front hood badge,side potmetal chevy emblems and door/window handles,in and out.
The knobs are maroon plastic not chrome plated pot metal
Everything else was painted,the dash the grill,the hubcaps and even the bumpers.....I coulda missed a little but you get the idea.
back to your specific ques,
Its probable that toward the end of the model year run the grills were painted to go along with Govt Restrictions
Regards
