Factory flatbed chassis question

[jmack91z28]

I ran across a 62 model c20 4 speed with what appears to be a wood flatbed. The owner acquired it in an estate sale and knows little to nothing about the truck.

Let's assume worse case that is was a factory order with the flatbed or it was just a cab and chassis order, would the chassis be built differently to keep me from buying a fleetside bed and installing it in place of the flatbed?

I know this is somewhat of a vague question, but I'm sure there are people here that have kinda ran into this issue before. Just thought I'd inquire before I pursue a project that can't be done.

Thanks, Jason.