'64 Valiant door locks

They're totally different. Even the hole in the door is a different shape. The '66 and newer locks have removable links on the back so you can swap them from side to side whereas the '65 and older don't and are RH or LH only parts. If the link on the back breaks off,(the usual problem) there is no way to fix it. I've seen door that have been converted but it would be a bit of work to get the hole right and the linkage might a real trial and error exersize. I don't know anyone who is making a reproduction part yet so used is probably your only option.
Thanks, Mark