Welcome.
Probably the moisture it would collect that did much of the damage, unless the wood were acidic... consider yourself lucky if mice did not ravage the bike making nests.
Original exhausts rotted out pretty bad, so it may not be something around any longer. So, don't keep your fingers and toes crossed to hard.
The bke looks pretty nice under all those cobwebs and sawdust. Don't keep us in suspense too long. Share some pics of what it looks like, warts and all. The aluminum may clean up on the buffer in some cases.
Don't rush out and buy tires, but don't go riding on those. Hopefully they held air pressure.
How long has the bike sat?
Some oil in the cylinders before you try to start or kick it over. Sometime the rings will rust to the cylinder liners...so a bit of oil and letting it sit after feeding it that is a good idea.
Patina is sometimes good, depends on what you want. It cannot be recreated and they are original only once is the adage.
