The problem of using “old recovered X” is whether there is sufficient “old recovered X” for a production run whether the production run is a real produce keys for sale run, or repeatability for anyone using your design files.
If you have your own 3d printer you can play making one offs and improving. But for a design to be reproducible to the extent that I can get the model files, print one, find a old X and strip and make a key that works as well as the prototype is hard.
It’s an interesting subject. Maybe a run of contacts will need to made at some financial risk to make 3d printing repeatable. I’m doing something similar at present looking at some way of making a repeatable 13 (or 23cms) antenna design that can be easily built by people who know which end of a soldering iron to hold but don’t have basic metal bashing facilities. Whilst making money out of the idea would be nice, my aim is to make it so more people can buy some cheap(ish) microwave gear and make up some real gain antennas and go and have regular QSOs on these bands as easy as on 2m and 70cms.