Yes, much like my Ram 3500 was "incomplete vehicle" until I put the flatbed on it. Now it's a truck, because it has a cargo area (there are DOT requirements for the minimum size).
When I have something other than the bed on it, it's no longer a truck. If there's nothing it reverts back the incomplete vehicle, if it's a camper it becomes an RV.
I learned an awful lot about this stuff when I had that Pete, used as an RV and insured as such, and trying to put living quarters on the back with room for the Jeep behind that.
No dice, so I figured that if I have to have it registered as commercial (this was in CA) I might as well just build a toy hauler for it.
So it stayed a tractor, with no (or not enough) square footage for cargo. But I do have hand trucks (dollies) and such that are indeed trucks.