If you are not taking the skin off, you will not be able to tap out the ID plate fasteners from the back side. If you are removing the skin, you can tap the fasteners out with a small punch and reuse them. A quart of epoxy primer should be enough for 2 exterior coats. At West Marine, the quart of epoxy is around $53 plus you must purchase a quart of reducer to thin the epoxy. Reducer is $38.

The back side of my first pump was dimpled from laying on the ground for an extended period of tim, but that was fine with me; sandblasted it, primed and painted, and it works for me.