Ive seen the 53 style grilles "cobbled" into the 54 front fenders. It kinda works and it kinda doesnt. You have to ruin the fenders to do it. None of the bolt holes line up so you have to drill your own. You also have to cut the grille opening on the fenders square,instead of rounded at the top corners.
The filler panel(splash pan) is different. And the 54 fenders have indents for parking lights.
Hate to see ya ruin a good 54/55 front end,but its your truck.