As long as there is no rust on the frame and cook box it's a solid deal.. As above poster said, the floor, back panel, and lower side frames where they join are heavily rust prone, as is the cook box in the front where the grates rest and lower sections
We just took three junk s620s today from customers with the above issues
Also make sure each burner lights ok and the ignitors are built into the valves and tend to go, each is about a 30 dollar part or you can just buy a manifold for 160ish. If they don't light but the wire is present and not burned and the metal bracket that directs the fuel into the electrodes isn't rotted, it's probably just spider nests inside.. Bring a ratchet, extension, 7/16ths socket and 3/8 socket, a Philips head, and possibly a 5/16ths if it's the one year they used that to hold on the front panel instead of a Phillips head.. Knobs off,phillips screws or 5/16 bolts on each side, panel will be off..