Thought I would mention that though you can use 65 and 66 fastback trunk hinges on either car, if an owner is focusing on originality there are visual differences between the different versions.
Given the Dec date its pretty well defined. If you share a picture of the other side of that passenger hinge then the version could be determined, though from this angle it appears to be from a 66. Also if it's a 65 version the spring arm would be the double thickness version also rather than the single thickness seen on later hinges
Very reasonable prices if the hinges are tight!! IMHO Good luck with the sale