I did a little experiment on my 54 where I used a earlier radiator shroud panel and tried to bolt a 54 latch mechanism to it. It fit fine. From what I can tell the only difference between the panels is the 54-55.1 has some wiring loom hooks riveted to the back side the earlier panels do not. They will interchange.
As for the hood latch itself the only difference between the 54-55.1 and the earlier latches is the release arm on the 54-55.1 is different to accomodate the new style grill. The old latch will function just fine though with no interferences.
