[alsriv2]

Best thing to do is to contact the agency who will do the inspection to find out your particular state's requirements. Swapping a VIN tag is a Federal Offense and could result in some legal implications for you if and when caught.
Each state has its own rules. Some just want the cab VIN, some want the cab and frame VIN.
Each member here has had there own dealings with this problem when it comes to projects, and each state makes their own rules, but the rules have to be followed so you don't get into trouble.

Good luck in getting this situation solved easily!