There are definitely factory Mini-14 mags just as you describe.

And Bill Ruger did indeed push the mag capacity issue.  He sent letters to everyone stating that by eliminating high-cap mags, the "thread of assault weapons" would be removed.

Of course, he was very worried about two things: his cash-cow Mini-14 being banned, and the fact that the 17-round-capacity Glock 17 was selling circles around his 15-round 9mm pistols.

So, by bargaining away our rights in an effort to save his sales, he pushed the mag ban on the folks in congress, "explaining" to them that they could adopt a 15-round mag capacity limit and leave the guns alone.  Of course, that didn't happen.  Instead, Feinstein jumped on the mag ban idea, reducing it to 10 rounds, and ADDED it to the rest of the ban.  Of course, the ban WAS worded to allow the Mini-14 to be sold.

Ruger later (i.e., after pissing everyone off and seeing his sales plummet) tried to buy back people's favor by donating a million dollars to the NRA.  Some folks think that's good enough.  As for me, I'll only buy used Rugers.

-Troy