It's not illegal to remove and replace the tags on your own car where all the numbers match, and if you never sell the car it will not be an issue. The rivets used to attach the VIN tag are very distinctive and if they are replaced with standard rivets the change will be noticeable and may be questioned by a future potential buyer.
The rosette rivets can be purchased, but not readily.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching