matt eastman's info is good but not infallible. there are several things in his books he didn't get quite right. i've personally owned several brownings (not just supers) that were completely correct but shouldn't have existed according to his books.
the standard rule of thumb is 1967 thru 1969. i've personally owned brownings from 1971 that had salt problems. per schwings book - as noted in a previous post - all that wood was destroyed in 1972. i've seen 1966 dated guns with the problem but i suspect those had their # assigned in '66 and weren't finished out till 1967.
were it me, i'd look over very carefully a 1966 gun. i'd avoid period a '67 thru '70 unless tested negative and proven and i'd be more careful of a '71 than a '66. by 1972 i wouldn't worry about it too much as long as there were no obvious outward signs.
roger
