Funny, I have a pair of the fronts from my 91 318is. Actually was going to clean them up this week and post them for sale. I believe there is no rust and will confirm. The come with the wheel bearings, back plates, and the rotors, which I can removed if not needed, to save weight. They are Balo's and never have been resurfaced. I can get the age and mileage if interested. I just don't have the ABS sensors as I re-used mine when I added the e30 m3 suspension.
Let me know if interested to clean them up, follow up on the rust and take pictures. I am in Miami, FL so not sure the shipping cost to your zipcode.