Personally I like the '67-'68 grills on everything but I've seen some low GMCs & some 4x4 '67-'68 & '71-'72 trucks that I really like also.
Basically, do you own the truck?? Then do it how you like it.
I have a '71 Blazer and bought a '68 swb for the front cap. A friend is gonna take my '71 front and put it on the '68 and build a ground scraping stepside for his shop truck.
To each his own, IMHO
Here's a few I like that are backwards from your preference.
This is probably my favorite GMC of all time.
And this is probably my fav 4x4
but this one is pretty cool too