I came across 3 30 round mags for a Mini 30. Most likely from the 80s. There are no markings on them at all. Any idea of who they could have been made buy?

If they are from the 80s and not marked
They are probably junk

The only two good mags in the 80s were for the mini 14 were factory and PMI
PMI did not survive and they bring a premium

Gun mag warehouse has some tapco 20 rounders for the mini 30
Not the best but will work

Natchezss.com shows 20 round factory mags in stock for the mini 30

Magpul would be another option, you just need to search for them online
They would be better than tapco

There’s a thread on PerfectUnion forum covering how to identify aftermarket Mini mags, with pics, both current & out of production.

@wonderson Would you be able to provide a link. I went over to the sight and couldn't find it.

Me thinks it is in this thread: https://www.perfectunion.com/vb/ruger-mini-14-mini-30/45746-mini-14-30-magazine-links.html

As said above, if there are no markings on those 30 rounders, they are pretty much assured to be junk.
I post a lot on perfectunion, and my main area of interest is the Mini-30 (O.K., my only interest !)

Besides the Ruger magazines, the ONLY Mini-30 mag that you can stake your life on is the South Korean made KCI.
They are built stout like an AK mag, thicker feed lips and body and a rust free Phosphate like finish on them.
If only the Ruger mags were as nice.

Mine lock in solid with no wiggle like the Ruger mags. The locking tab on the back of the mag is a bit oversize. I had to take a file and hit the bottom of the tab a few strokes so all of them would lock into my 2 Mini-30s. I'd rather have that than really loose magazines.

They haven't been imported for a while, I got some of mine from a guy on Gunbroker, and some from the classifieds on perfectunion.
They typically go for $25 to $30 each.
The Mini-30 has been called "America's AK" This is even more true if you have some KCIs.

Thank yall for the info.