Far as I know, MM is using a stock pump.
As for the broken one I can assure you, something got into that pump. Just looking at a few nicks in it tells you that. Mine was exactly the same way. Nothing is wrong with the stock pump as far as I know, just a poor oiling system built into the block.
I would rather coat the pump housing than the pump itself, being that it is aluminum and therefore more prone to wear.