I recently bought a new wet side for my mp 10, this morning I was cleaning it and noticed a lot of rust on the side of the magnetic circle. Pics bellow. My question is are these replacement refurbished or not as good as original ones that are sold in the unit? My original one lasted for 4 years and I only replaced it as it there where a lot of scratched and on the magnet. This has only been in use for 6 months.