The Model 55G was made from 1961 to 1965. Unless equipped with the Marlin Micro-Choke, it has a 28 inch full choked barrel. This is not a Goose Gun. The Goose Gun had a 36 inch, full choked barrel. The Model 55G sold for $39.95 when it first came out. There were 12,351 of the Model 55G's made in 12 gauge. The 55G is a Glenfield version of the Marlin Model 55 Hunter. The Glenfield line of guns was a less expensive version of Marlin's first line guns, that used a less expensive type of walnut stained hardwood for the stocks, instead of walnut that Marlin used on the first line guns. Otherwise there is no difference.
I hope this helps.