I guess the FSP can stay, I didn't realize it would vanish. I know they make risers for the scopes, probably go that route. I might order a hand guard rail system instead.
If you want to remove the FSP, I say go for it. The pins in the block are most likely tapered, so they go in one way / out one way. A taper pin punch and sight block are handy, but not necessary.
As far as the finish go's, try carburator cleaner first. It's possible it's spray painted.