The engine was extensively scanned recently (https://www.3dsystems.com/learning-center/case-studies/reigniting-f-1-apollo-engine-geomagic-solutions https://www.

The engine was extensively scanned recently (https://www.3dsystems.com/learning-center/case-studies/reigniting-f-1-apollo-engine-geomagic-solutions https://www.3dsystems.com/learning-center/case-studies/reign...), so plans of what was actually built exist. If we don’t have plans for the rest, we could use that technique on the other parts. That doesn’t mean we can build a 100% copy, though. Apparently, some of the welding requires techniques that have been replaced by better methods, and welders who can replicate the original do not exist. I guess that’s solvable by using robots, but if, e.g., 3D printing or even glueing works better, and the goal would be to get a rocket that size again, why bother?