Welcome! I too and a new CB400F owner -- though, I paid a pretty price for mine. There is just something satisfying about getting a decent bike cheap or free, and then bringing it back to life, so kudos to you for saving this special bike from the dump.
Yes, a CB400F is as great bike to get as a freebie. The paint on the fuel tank looks to be in very good condition, and you've got the original exhaust too. All-in-all, it looks way better than I'd expect for having been outside for 15 years. I would have expected the sun to fade the paint into oblivion, and since I live the wet northeast, I would expect all the chrome surfaces to be red/brown with solid rust.
Yes, pull off the touring stuff, replace that hideous seat with a proper one, spend a good day with some chrome polish, and it'll be looking great!
Enjoy!