Upgrading Door Locks

I currently don't have keys to my doors to my '64 Dart but I have some spare door locks from a '68 C-body. The ignition on the Dart has already been changed to the newer style of key and it would be nice to make the door locks match.

My question is: How do I make the hole to position the newer style locks properly? I have access to Greenlee punches- so do I make the new hole concentric with the current one or does it have to be offset?

Thanks!