The best advice is to avoid the salt year serial number range. If you're bargain hunting, it's your dime and it certainly pays to know what's what. I spent my "two dimes" on a '68 Diana 12 ga. 28" field and got back change and a gun in a grade and condition which I would not have owned otherwise. Even if you make it a rule to eschew suspect guns, human nature being what it is, you can bet your booty someone somewhere has restocked a non-salt Super with a salt-era takeoff for reasons ranging from expediency to greed. jcj has it right; if the action bar, tangs, springs, forend mech and barrels haven't rotted away by now, it doesn't stand to reason that they will decay merely on the say-so of fastidious collectors.
jack
