Any Browning gun from 1966-1971 should be carefully inspected. A-5s, Supers, T-Bolts, even pistols. For the Supers, S, V, F, J 67-71 will cover 12, 20, 28, and 410 gauges. If the Superposed has a long tang on the trigger guard, it is widely believed this gun was not affected. The long tangs were phased out by late 67 or early 68. If you see a nice Super with salt damage, don't be afraid to buy it (well below retail) and then send it to Arts for repair. He can save nearly any salt wood action...the wood is firewood, no matter how pretty it once was.
Diana signatures are usually in the middle bottom, but could be anywhere on the bottom back corner.