serious questions about "USA" mini-30 magazines

[amalgam]

don't bother flaming to say they're crap.
I have to live with the magazine ban.

I saw some "USA" 20 and 30 rd mags
for the mini-30 at a gunshow today. I noticed some variations and hope someone here knows about them.

"type 1" had no rib on the back of the mag (flat part facing to the rear when in the gun). these also had a baseplate which did not extend past the sides of the mag.

"type 2" had a raised rib down the back, the baseplate extended 1/8 inch on both sides of the mag, and the baseplate had a hole in it with a 'catch' sticking through it (making it VERY easy to disassemble). the bottom sides of the mags were bent out 1/8 inch to
engage the slide-grooves of the baseplate.
some had "USA Magazines" stamped on the side, near the bottom.

the questions:

were these produced at different times? why the diff ? which is the earlier production? I would guess "type 2" is earlier, because it looks more difficult to produce. I'm guessing later mags were simplified to speed production (especially right before the ban).

Is there any difference in reliability? quality?

I'm thinking mini-30 mags availablity will dry up before the mini-14 mags.

comments and information, please.

[Grayfox]

I have several of the type 2 mags. I've never seen the type 1. The clearance between the mag and the bolt in the Mini-30 is very tight and just a slight bend in the feed lips will cause the bolt to hang and jam. It's easy enough to fix once you know the problem. I've had to adjust a couple and haven't had any more problems out of them. I think the bent lips probably come from clumsey warehouse workers. Considering that they're cheap and plentyful, USA mags are ok with me.
FWIW: I prefer the 20 round mags. I have one 30 round that came with the rifle and have found it too big. It makes the gun awkward with that much mag sticking out the bottom.