a few questions regarding vin/reg

[SmokeShadows]

i was looking for help on identifying some of my questions and problems, i recently became the new owner of a used and abused 68 gmc pickup truck that has been around the block a few times, there is too much wrong with it to list but im slowly trying to bring it back to life.... but anyhow FIRST off i would like to know if its suspicious that the truck has no vin, not on the dash in the window corner, no plate riveted to the door frame(although there is holes), no vin stamped on the driver side framerail next to the power steering pump, is this strange and should i be concerned, and where else could i look for a vin? i am in the process of jumping through dmv's hoops cuz the truck has no paperwork,title, or anything, all i got is the license plates, there is no spid label on the glove box, i have reason to believe the cab was swapped because i gotta go through the salvage process once i get the title, i will post pix with more questions later but i want peoples opinions on what they think and or what i should do