I think we're talking about highly-skilled precision welders who built things like the F-1 rocket engine. These people didn't work for NASA in the 1960s: they

I think we're talking about highly-skilled precision welders who built things like the F-1 rocket engine. These people didn't work for NASA in the 1960s: they worked for private contractors like Rocketdyne. NASA doesn't build rocket engines, and never has.