If you do it right and not swap parts and actually put it back together the exact right way with it timed, then yes it's possible.
Being able to do much of anything to get it working again if there is corrosion in it, Highly unlikely.
Post up some pictures of what you find inside.
Thanks for the reply!
I took it apart. Only problem I had on taking it apart was the two screws holding the plate on the side. They were punched on the side to keep them from backing out. Finally got them free without stripping them. Anyways, the inside had no corrosion, fairly clean, just a little black residual here and there.
Before taking it apart, I noticed the slide would move, but not freely and the front lobe was more stiff moving than the other two. Taking it apart the locating pin for the front injector line behind the cover had the pin broke off and jammed and the piece that it was supposed to locate was turned some.
So, my uneducated guess is the turned piece was allowing constant fuel to the front cylinder and the stiff slide was from the broken pin and the damaged bottom landing dragging on the control sleeve.
The whole inside of the pump was wet with fuel so do you think the reason the back two were dry is because of the front one taking all the fuel with the turned "fuel inlet sleeve"(not sure what to call it). I did notice the oil smells like fuel and is thin and over full, maybe from too much fuel dumping in the front cylinder?
Also, on the damaged pump housing, I think it'd be ok, because it seals the fuel on the top not the bottom? Is that right?
I'll try to attach some pictures of the broken locating pin, the damage housing, and all the parts out. These are before I cleaned anything.
Thanks!