Surprise!  The well known GMC grilles from 1949 through early 1955 use the same bars.  This includes the more popular ½ ton through the very large over the road and quarry trucks.  Chrome or painted, the four horizontal stamped metal bars are identical.  Look at the following photos.  The grille bars interchange!

1949 - 1955 GMC Grille
1949 - 1955 GMC Grille
1949 - 1955 GMC Grille
1949 - 1955 GMC Grille
1949 - 1955 GMC Grille
1949 - 1955 GMC Grille