@mk70ss: Thanks for sharing your find. Great photo! I would have rescued that one also. It is good that you got two magazines with it. It is getting nearly impossible to find magazines for the 39, 439, 539, 639, and the 39 compact model series, and so if you run across more magazines, I would grab them.
As for the unpopularity of single stack magazines, that may change. I hope I'm wrong, but I'm afraid that before the current administration leaves, there will be a federal ban on high capacity magazines.