The salt curing process began in 1966 and continued until around 1971. There are salt wood guns for a few years after they quit using the process. Aside from the serial number giving you the date of mfg. it is pretty easy to tell if a gun is affected. Just look at the metal right next to the wood and if it is in any way pitted or corroded then you have a salt gun.

R. Craig Clark
jakearoo(at)cox.net