Concerning the reasons for the quality issues I believe Jaco1234 has a very good point. Others have described potential reasons that are valid also. For a company that has been in existence for 77 years it seems unlikely that SOPs in quality assurance could have gone unattended or sporadically followed for such a long time. I did not see anywhere on the website that states they are ISO 9000 certified.
Granted, the wonderful world of employee commitment to quality assurance has been a major challenge for manufacturers for like forever, has only gotten tougher lately.
I have a 52-1 model number 55533, so one made in the early to mid 60s. I have 3 original mags, box, tool, extra extractor, blah, blah, blah, so yes, I appreciate the firearm. I should be receiving 2 mags from Triple K on Monday or Tuesday. I am a little concerned about these issues mostly with the possibility of them getting stuck in the gun now that I have had time think more about it lol..
I can let you know how they work with a gun made back when the tooling was in original condition if that would help.