They are not expensive on ebay, But all say only fit 66 and up. Is there a difference in 65 and 66. The body styles are so similar , I don't see a difference in the two.
Advice.
You are correct in that the 66-up locks are not expensive; reason is Chrysler changed the lock style (and sheet metal where the lock is inserted) in 66. Swap 66 doors to your 65 and 66-up locks drop right in. Conversely, if you do a bit of modification on the door lock opening on the door, you can get the later locks to fit.