If the paper title VIN decodes to the truck you have, as Tim has asked you, then check the motor number as said. If that does not match normally you would tell the MVD that it was matched to the motor and the motor is gone and they will have a procedure for that. HOWEVER, you have a serial number VIN tag on the door. So it could be stolen, paper title from another truck or tag switch or pieced together or anything. Could be a legit reason. That will raise suspicions and you may go on a Government, red tape, costly, time consuming journey.
Post the Title VIN and post the plate Vin.

Note to others: Don't buy a vehicle with a title that does not match an original serial number fastened or stamped somewhere on the truck. Unless you want to "take a ride on the wild side."

Buyers Do-Do list.
1. Check the title and vin plate match
2. Check the rust
3. Check 1. and 2. again.
4. If 1. is present and 2. is not present = good buy
5. Any other combination of 1. and 2. = good bye

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn