Update: Well, I have to give Bosch credit. I brought the router to a service center and included the bases. One person in tech support said they'd replace the bases. Noone else did. They didn't say they would when I brought it in, but I left the bases w/ them.
Got it back a couple days ago - motor nicely recased, and got two new bases - neither one Magnesium.
So they came through! Hats off to Bosch.
Perry