Santa Fe 03A3 actions were around before GCA68, I don't remember if National Ordnance were or not.
Both aftermarket of course, & filled a need at the time.
I think they were investment cast receivers. National Ord. had Elmonte Cal. markings on them.
Santa Fe,,I don't know, but I take it they were made in the USA as they were still sold after GCA'68. That would have ended the importation of them at least till '86.
They were both very common when there were no military surplus imports from 68 to 86.
The National Ordnance usually had a better overall fit and finish than the SantaFe branded ones.
The 'word' was that they were soft,,or brittle,,or poorly headspaced and fitted up. They'd crack,,or blow up,,or the lugs would set back..
I never saw one that failed. The ones that I did check headspace on passed just fine. I had no idea of how many rounds those rifles had fired of course.
The 03A3 wasn't the tightest fitted rifle even put out there, and these aftermarket versions were no different in their operational feel.
The ones I saw were all US Military Surplus parts except for the aftermarket receiver.
Milspec parts were so cheap, it didn't make any sense to make any of those. It was just the receivers that were needed to build rifles for resale,,or sell the receivers themselves.