You may have to fill some holes where the fangs of the '54 grille meet the lower pan, other than that, any of the '53-'56 truck grilles should be a bolt-in swap.
Having had a '53 grille in my F100 I can honestly say that they are a direct swap Sent from my iPhone using H.A.M.B.
Saw a nice 55 grill for sale recently at a local swap. Looks new, chrome, $400 with hood emblems. If anyone is interested I can get you in touch with the owner.
My panel has a 55 grille, it's just the grille and lower panel and then you choose what turn light housings you want to run (I went with the 55).