Manufacturers of commercial aircraft went down this road 2 decades ago, prototyping mockup components; and, working out issues before tooling up for actual parts. Now actual parts are fabricated to shed +10% weight over results obtainable with traditional machining/ fabrication techniques.
NASA needed a fuel injection assembly for an F-1 returned from museum storage. Traditional supply operations forecast delivery of +1 year. Printing a working unit was achieved in a abbreviated time frame.
Wow! Great article, I had no idea they are thinking of bringing back a new version of the F-1. Truly a mighty beast.