I picked up a P10-45 Limited recently.
Haven't shot it much, but seems to function perfectly. Also, very little indication that it was shot much by the previous owner. I'm going to put it at under 200 rounds through it in it's lifetime. I also prefer the Hogue Grips on it, makes the little booger easier to hold on to.
Mag release is plastic. Also, mine does not have regular handgrip bushings like most 1911's. Instead, the grip screws thread directly into the frame. Had to make a trip to the gunsmith to clean the threads the other day, need some new screws now. I do not know if the P12 has this same concept/design, but wouldn't hurt to double check the threads and screws.