I just picked up some NOS lenses for my 63 valiant wagon too. There weren't cheap but nothing like them. Any used lens I have found was so faded .......
You are so right - nothing like brand new, un-faded and un-cracked lenses.
When I bought my tailgate with the power window (not yet installed) from a 63/Dart (or maybe Valiant) I got him to include the round back-up lights as well as the front turn signals.