[Cannonball]

Hi folks,

My master cylinder is leaking profusely from the rear and I was wondering whether the mc/booster combo is correct/original to the car and is worth rebuilding. Everything has been painted black in its previous life. The master cylinder does show the application code EB on the front and has dual bleeders and dual valves. The underside has "5470408" or "5470409" cast on it upside down.
The booster has an upside down DELCO MORAINE stamp. I cannot make anything of the characters on the front of the booster tab, the rear has "042" stamped on it, can't quite make out if there is an additional character after that.
If I am to spend the money and effort to rebuild it, as I understand the booster is plated in zinc dichromate and so is the mc lid. What about the master cylinder itself, some say as cast, some say flat black, would gray zinc phosphate be a suitable finish for it and the valves?

Thanks.