30 vs 9mm AM III magazines?

I’m not sure, but I think the magazine with the black follower is a International Armament Corp magazine: https://www.brownells.co.uk/AMT-AUTOMAG-III-MAGAZINE-30-CARBINE-8RD-SS-INTERNATIONAL-ARMAMENT-CORP-Silver-8-Round-Stainless-Steel-Auto-Mag-III-100030933

I wonder if some of the differences in the guns and or mags might be tweaks or changes made as time went on with trying to fix problems and inconsistencies that they had. Change an angle a bit or larger ejection port to help with stove pipes or smaller trying to add weight. Also wonder if some of the differences in clearances could have to do with the fact of how many times they moved. You know, loading the machines up and moving them then start cranking out more guns without checking calibration of machines. Just a thought. Then throw in changes that Galena could of made. I have an auto mag 2 by Galena that parts will not interchange. (Which is also a question of mine. Did they not get all the blueprints or was they also trying to improve on problems?) Then to finish it off, as old as they are and limited parts, it is hard to say if some of these mags and guns we have are piece milled together on the street then passed onto the next guy. Just my two cents which now cost eight cents.