Just sent you the PDF of the manual and parts diagram. You should have no problem finding a key on Ebay using the number that's on the ignition- Some has an add up all the time- they aren't cheap, but it's better to get the right key because it works the fork lock and the seat lock as well.
I have heard the same about the seals as well, but although mine sat up it fired right up and has run fine ever since.
One thing to be aware of- the fuel petcock is not the usual on/off/reserve. It is vacuum operated, so the positions are On/Reserve/Prime. Don't leave it in Prime, or your crankcase will likely fill with fuel. If you need to get fuel in the float bowl- use prime while you try to start the bike, but after that just leave it permanently in the "On" position. I've never moved mine since I got it sorted.
Have fun! Feel free to IM me with questions. Dave
1980 Vespa P200E