When I replaced the wheel bearings this spring, I replaced the races also, plus the grease seals. I got everything from this place.
They are real good to talk to, very knowledgeable. Usually the gal that answers your call can answer your questions, if she can't she will transfer you to someone who can. If you look around on their web site, they have answers for just about all the questions a guy can ask.
I can't answer your question on the magnet. I just can't picture it sitting in there right now.