What Jerry said. Cabs are the same. Only the COE is different in the front half.
As far as the hood brace issue, if by that you mean the cross support at the rear of the hood, it should be the same between Chevy and GMC, although the front of the hood is different. It should be fairly easy to find a decent hood to replace that piece. I don't know if that piece is reproduced.
Cool old truck.

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