I've seen 65 light on a 66 and 66 lights mixed in with the 65's. the one person (65 and 66 lights) I was able to look at his lights and talk to said he had to open the hole and mounting holes up a bit on his 65 to accept the 66 inboard trunk lights. trim is different for sure but nothing a mig can't fix. I'd go for it if it's cheap enough.
looking at those picture I see even the 65 has a slight drop on the passengers side trunk light(even though the whole trunk is low in that pic for the 65.) almost all the 66's I have seen do this, it must be a factory oops. I worked mine out a lot closer but it was a pain in the #### getting it right(or at least a lot closer!)