Nice score. I finally found a 22" Weber in in LA for $30. One was posted used for $60 and about 1 mile away and another had been cooked on 2x and was $30, but about 30 miles away. I had to make the drive and I'm glad i did. She said she had a ton of calls, but she held on to it for me. Her husband was glad that it was going to a good home and gave us a brand new charcoal chimney. We promptely added grill 6 to the family, cooked up some steaks, and I've since modded the lid to fit my UDS.
I bet some sand paper and wire brush, a nice thick coat of primer and a satin paint and you'll be in business. In reality the inside looks good so as long as the paint doesn't burn off and stink up the place you are probably safe just the way you are. If you do decide to paint I satin won't whow as much grease as a flat paint, and should be a little easier to maintain over a high gloss. I've used satin over gloss in my engine bays for the same reason. good luck and nice score!!