Sorry to contradict you Ron but...
Here is a 72 or 73 (I can't remember which) with a 1970 grille. I think the mounting brackets changed from year to year but I don't think that matters. There is no electrical wiring involved Marcus because the lights are not part of the swap.
This car belongs to a guy called Duncan Watts and is all steel with iron headed 440. It runs in the mid 11 second range I think. Pretty damn fast anyway.
Now then if the question had been should I swap my 72-74 front end for a 70-71 I would have said no!