Cimatti looks stock and pretty solid, but except to still do some usual things to get it going. Clean carb / fuel system, swap out or clean points, and just a general tune up. I saw you mentioned they went down to $400, so if you get there and it has good compression i would probably bite assuming you dont mind getting your hands dirty to get it going. $400 would be high in my area of ohio but in CA thats probably decent for a solid unmolested moped. The Cimatti uses the great V1 engine that will be reliable for you.
Also, except to change some wear items down the road. Tires, cables, etc... thats not a reason in my book to walk away from the bike but be aware. If you were planning to buy this bike and make money then walk away, but it looks decent for something fun to work on and ride.