If the discoloration is all rust, then the bike will be worth a lot more after being refinished. The "it's original only once" mantra has limits. I mean, rust, dents, road rash and missing/damaged parts weren't original, either. Beyond a point, it's just fugly. Give it a good cleaning, see what you're working with. The chrome is shot but it might clean up acceptably well. Once there's rust, the plating has been penetrated all the way down to the base steel; the extent of the pitting is far greater than you realize. Those rust spots are just the tip of the proverbial iceberg. Two upsides...first, there may be enough intact plating to get an acceptable shine back, for a while. Second, chrome is chrome; these are all bolt-on parts that can be re-plated anytime you like and fresh plating will only increase the value of the bike...along with it's visual appeal.
If that is the original flywheel cover, then this should be an early "silver tag" model. With nearly all of the hard-to-find early "silver tag" parts still on the bike, it's definitely worth restoring...if that's your goal. From what I can see, this bike is remarkably straight and complete.
There are some items I'd replace from the get-go: brake shoes, tires, chain, air filter foam. Brake shoes don't age well and can delaminate. Tires dry rot and turn crunchy. The drive chain wasn't that great to begin with and won't improve with age. Beyond that it will come down to what works as it should and what doesn't.
Engine condition is a bit of a crapshoot. If it still has full compression, then cleaning the oil spinner might be about all that's needed...that is long overdue. Check the oil seals for seepage. They can replaced without pulling the engine from the bike. However, it's a lot easier to replace them with the engine apart. Specifically, in this instance, I mean R&Ring the kickstart shaft oil seal...way easier while the clutch cover is on your bench. It's also easier to repaint the clutch cover off the engine.
Looks like the fork is in desperate need of a rebuild. That's a messy job, but not difficult or expensive. $75 worth of parts will take the slop out of the inner legs and give you new gators (boots) + caps, improving the steering & stability. That'll also give you a chance to check for straightness. I suspect that these are straight, no evidence of the bike ever being crashed.
The mechanical stuff mentioned thus far should be sufficient to get the bike running and safe. If you weight more than ~150lbs, you'll soon want stronger rear shocks. See what you like and don't like, from there.