If you are thinking of investment, don't do any repairs, repaint, or modification. It will take a huge chunk off of the collectibles value.
If it is just for fun an use, then the only thing I can say is during disassembly expect it to try to 'explode' when you take the deck off. If the spring has shifted on its mountings it might try to break free. Work in a clear area (or disassemble/reassemble in a box), if the spring gets loose at any stage it will do so violently and could send other parts flying.
If you are going to lube, it might be better to use graphite on all working parts instead of oil. The only exception might be the prop shaft if it allows water to come in.
