I wanted to pass on what I've done and the results.
Still having the mag disconnect in place, I cleaned and applied 3 coats of S&W dry lube to the upper 1/3 of the front of the mag. It uses a dry lube called Cerflon.
I buffed in between coats with a clean cloth.
It removed the trigger creep and stacking that I had before with the new MecGar mags. They are nearly as good as the original mag now.

As WVSig said, the original phosphated mags shouldn't need this
and may actually make things worse. I'd leave the phosphate coat alone.
This is what worked for me without any alterations.YMMV