A few weeks before my car went to the shop, I was talking to a local '71 GTX owner at a cruise, and of course I was very interested in his restored original AC system. He told me something the shop owner working on my car didn't know, which is that original driers can be restored. They cut the bottom off, replace the desiccant, weld the bottom back, and paint, to restore the original. Glad I found that out, as mine is now being restored instead of getting replaced!
The GTX had been converted to 134. The owner told me it works so well, his wife sometimes complains it's too cold and he has to turn off the AC!