Marlin Glennfield Model 50

Ok, guys, need a little help from the Marlin shotgun experts out there. I just traded a Marlin Model 60 with a no name Chinese 3-9x scope for a Marlin Glennfield Model 50 12 ga shotgun. I need a little refresher on Model 50 history. There is no serial number, so I know it is pre '68. can't remember anything about it's manufacture. The stock is in nice shape and the barrel is still like a mirror. There seems to be no finish on the stock other than the stain. Is this stock or has someone refinished it? The only modification on it is an old red rubber butt pad with no writing on it. Will add pics soon. Can't wait to shoot it. My first Marlin Shotgun.