Okay, forget it. I must have imagined the whole thing.
I don't know what the specific differences are between the 1200 and the 1300, because I have never been a huge fan of either, although I sold a good number of 1300s and have also shot a few and never had any issues. If they are the same, why did Winchester "revamp" the 1200 and change nothing?
Remington bought the rights to the Ithaca Mag 10, and they were almost 3 years working out a "few kinks" in that design before they re-released it. I don't know exactly what they did. I did own a Mag 10 and replaced more than one broken part on mine, and on a bunch of other peoples'. I have yet to see a Remington Mag 10 with a broken part, and they look about the same too.
They were not 120s. I did not imagine that. the Winchester design team no doubt had good intentions with the 1400 too, and it was a total flop. They never made a decent semi from the time they passed on John Browning's Auto 5 design until the Super X. The post -64 Model 70 was a great improvement too, no?