I'd be more worried about that rubber shock bushing than the mount itself. That mount is a very beeffy piece of metal--I had a good look at it while my frame was off. It's hard to tell, but it looks like rust-colored rubber that is flaking off, more than lost metal. I'd leave it, and when it's time for shocks, which I suspect is not so distant, clean up what rust there is with a wire wheel and POR15 it.