New looking for help

[98sonoma]

Hello, I've been looking for a C10 for a while that I can work on with my boys as they get older. I found a 72 C10 SWB for $2500. They guy said the ID in the glove box doesn't match the original VIN. How big of a deal is this? I'd like to eventually tear the whole thing down to the frame and build it from the ground up. Now the guy doesn't want to share the VIN for some reason. Should I be worried? It's a 4 hour drive to even check it out. I can post pics of that would help. Just looking to see if I'm being taken or not. Any advice would be appreciated.