Model 60s were made with the higher capacity tube along and the auto hold-open from about 1985 to 1989.
Before 1985 the auto hold-open wasn't available and after 1989 the tube capacity was reduced to 14 rounds. A few years after that Marlin reduced the barrel length to match the shorter tube. This is a "real" Marlin... now that Remington owns the company you can do some Google research on the recent quality issues.
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