Carte gris moto

So, about two years ago , i bought a heap of a moto with the intention of using alot of the parts for another of the same model. So far so good.
The fella i bought heap from gave me the carte gris,but did warn me he had never updated it.Now i am asking if there is a process or a way to actually get heap back legal again.
I like heap, the carte gris shows the moto to be from 1988. Cg “scored out in 2019”
Any help greatly appreciated.