Before you do any assembly, talk to the VIN inspector. No point in tossing money in until you have it all legal. And with the front end open, they will be able to easily inspect the hidden VINs. Please research your state's laws on getting a vehicle titled. Some excerpts from Google are below.

If the jamb is actually cut where the VIN tag was, I wonder if it was totalled at some point?

"(17) The VIN is missing from my vehicle or 2 vehicles have been put together to make a new vehicle. What do I do?
The owner will need to bring in a certified VIN inspection (DR2704 available from the Colorado State Patrol), a record search (DR2539 ) for every VIN that is listed on the inspection, any ownership documents for the vehicle, any invoices, receipts or bills of sale for the vehicle, a photo of the front and back of the vehicle, a completed Colorado Assigned Vehicle Identification Number Declaration of Facts (DR2426 ), and an application for assigned vehicle identification number (DR2408 ). Secure and Verifiable Identification and current proof of insurance will also be required.

The application fee is $3.50. All documents are remitted to the State for approval. When approved, the State will contact the local Colorado State Patrol office to affix the new Colorado VIN to the vehicle and give the owner all documents previously remitted.

The owner will use these documents to apply for a new Colorado title, with the new VIN number. A $7.20 title fee, plus any applicable sales taxes will be due. Our office accepts cash or checks only."

"Steps to Getting a Colorado Assigned VIN
The first rung is having the vehicle inspected by a law enforcement official. This official will also fill out a form DR2365 which directs the emissions assessor on how to check the vehicle. The inspection fee is $20. Call your title and registration office for a referral list. While you have them on the phone, double-check whether the inspector will have the DR2365 form, or if you need to stop by the office and grab one. You will not find the form online.
If the vehicle is a home-built or a kit model, you will complete a Colorado Assigned Vehicle Identification Number Declaration of Facts form and then apply for the number by filling out the Application for Colorado Assigned Vehicle Identification Number (VIN). The fee is a $3.50 fee for this service.
Once the number is assigned you will take it and the completed DR2365 form to an emissions testing technical center operated by the Department of Public Health and Environment (CDPHE). For information or an appointment, call (303) 744-2442 (and press 3).
Passing the emissions test (if necessary) is the final step required to prepare the vehicle for titling and registration. From here, the process is pretty much the same as with other vehicles. Expect a $9.50 titling fee."

As you can see, the info is similar but not identical. It does look promising, though.