Contact Chrysler Historical.

You can get a copy of the IBM card. With that you can see if the SO number stamped in the core support and rear of car matches what is on the card.

If it does then you just have a case of Willie Everlearn doing something stupid by removing the tag.

If you have the tag just reattach it using JB weld. Nothing illegal about it. It’s no different at that point then someone that removes their dashboard from their car.

But I would have the vin run before going to all that work.