Mike,
Great news on finding the spring in there. Some times those are a PITA to find if they are missing or decide to "fly across the room" on their own. As for the rebuild kit, depending on what you need you might look for the oldest "old fashion" hardware store in the area, the one with dust all over the boxes of parts and take what you need and see what they have that will work. If nothing else you will have a great time roaming around inside there. If you need gaskets you can cut new ones from gasket stock material with a sharp knife using the old one as a guide or press the part onto it to give you a guide.
Good luck and let us know how it all turns out.
Tom