Yup, definitely check every square inch of the Jeep for rust. On the frame, check near the spring hangers and steering box. On the tub, be sure to check all the body mounts and under the carpets (if there are any).
I'd also check to make sure the Jeep drives straight and that the welds on the axles (where they moved the spring perches to) are good. It will probably have bump steer due to the SOA.