This is the first car I've attemped to restore ......a 62 Valiant V200 4 door.
I've found (gotten) most everything to finish this car except the door
handle and lock gaskets.
I'm sure these same handles were use on other models like the 'B' bodies
but how do find which ones used the same gaskets ?

There doesn't seem to be any parts interchange site out there.

The doorhandles on '62s didn't get gaskets from the factory. Neither did the locks. But, gaskets for the locks used through '65 can be had from Gary Goers. See this post for contact instructions.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Hmmm ........
I'm supprised to hear that .......
This car was more or less complete when I got it but I took it appart
many years ago and thought I had lost or misplaced the gaskets.
I made some gaskets from rubber (not great) but thought they would do
if I can't find factory type repros.
Without gaskets the handles raise hell with the paint.

I agree with you that door handle gaskets are a good idea. So are lock gaskets. The addition of little bits like this was part of Chrysler's overall improvement in build quality beginning in '63.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.