If bike have been "stored" sooo long time without turning engine, U have plenty of work to do:

1. Change all filters(fuel, oil, air)
2. Change all oils(engine and front suspension)
3. Change belts
4. Change tires
5. Check Valve clearances
6. Change spark plugs
7. Check all connectors and erthing points
8. Buy new battery
9. Clean carburetor
10. etc....

If You lost your regulator, You can lost also battery and also ECU(if regulator gives too much voltage to ECU!!!), surely charging system alternator(inside left cover) can "blow out", if Your regulator have problems....Btw, that alternator coast double to regulator...

I dont want to make harm to You by saying these things, but anyway Your bike needs TOTALLY big maintain to get all ok. I would be very carefull to start such bike after long time. Remember, if You lost belts, when engine is running, You have very expensive valve job then....

The belts are usually cheaper online here in the USA. But buying from a dealer isn't such a bad thing if you will need to buy a lot of parts over time.

I think you r regulator is probably OK but it can be changed once you get it running and have the opportunity to test it.