I agree on the "V" at the beginning of the identification number not making any sense. The "PK" definitely indicates a 4400 model and the 2nd "K" would make it built in November. "19183" is the unit number, with all truck numbers at each plant starting at 1001, making this one number 18183 off the assembly line.
Regarding the cab questions, all the truck cabs except for the 5000 series COE's shared the same cabs, doors, windows and associated components. Original equipment engines for the 4400 would have been a Thriftmaster 216, but you may very well find something different. If you can, look for and post the engine serial number as we can decode that to figure out what's in there now.
You are correct that the rest of the driveline/suspension are going to be different than the pickups, with the partial exception of the 4 speed "Crash Box", which will be basically the same except outfitted with an open drive output instead of the torque tube output setup.
Hope this helps fill in some knowledge gaps for you.
