[G&R's57GMC]

Yes they are different.
The rad support on the Chevy mounts at 2 points on the frame rails.
While the GMC mounts to the center of the front crossmember which is also different then the Chevy.

I’m using a Chevy frame under my GMC and using the Chevy rad support . This will require me to fab supports for the hood latch panel so I can use the GMC hood and grill .

Or I can use the Chevy hood latch panel and latch along with the Chevy hood striker support swapped from a Chevy hood and replacing the GMC hood striker support. Doing that I’ll also have to figure out a way to support the GMC center whisker of the grill surround .

Or do the above and use a Chevy hood .

Or ditch the GMC hood and grill and make it a ‘57 Chevy .