If you don't mind body parts that need a little Body Technician magic you can find OEM parts at reasonable prices.....but unless you want to pay large $$$ they will need repairs and paint.
The Chinese stuff is cheap but fit and finish leaves a bit to be desired.
Check availability from the factory by visiting StarTwins Trading
https://startwintrading.com/
or BikeParts
https://www.bike-parts-mv.com/mvagusta-motorcycle
If they are listed available then your local dealer can order from the factory too !!!
I have a few beat up body side panels if you go that route.
Decals can be found or made. There is a guy in Russia that sell kits for MVs. They're priced right and seem to be good quality.