GMC - Chevy what's the real difference?

[LT102]

At a parts shop the other day and listened to two guys talk about it being more difficult to restore a GMC than a Chevy 67-72 pickup. I have restored a 71' Chevy and just started on a 71' GMC and am at a loss as to what I am missing as to such a difference. I kept my mouth shut as not to expose my ignorance knowing that I was going to post this question and find out from those who really know. Other than the grille and some emblems what's the difference, if any.