You have two choices, mount the plate almost straight using
mismatched bolts (find some stovebolts) to the tailgate.

Or just hang the plate with some bailing wire.

What was the light for, If your stopped The horsemen might not look for perfection.

But to be serious you have done exceptional work.

1 1955 Chev one ton. 261 engine

3 1962 Chev c-10 261 engine
4 1966 Plymouth VIP 5.7 GenIII Hemi
5 1966 Imperial Crown Coupe 440 engine