I managed to the all-metal pump from the dealer. The variety of different pumps available can be found here.
https://www.carid.com/2012-bmw-1-ser...er=1&sub-model[Liter][]=3.0L
I've heard that the all-metal version was intended as an improvement to the original, and then it was determined that the bearings might seize prematurely. And then that supposedly led to an improved plastic pump being designed. But I could not say which is which. I gave the dealer the part number and the metal pump is what I got. Cannot say if there is an all-metal thermostat available. I will make certain to get all the related hoses as long as I'm going this deep. Thanks for that tip!