Usually I don't have a problem when I add a new firearm to the collection but I picked up a Ithaca Double today at a rummage sale and need some help. Left & Right side of receiver "Ithaca Gun Co. Ithaca N.Y." and engraving of a dog on point. When broke open, the serial number 334742 and "PATD" on one side and on the other is an "S" above the number "12". Butt plate says Ithaca Gun Co. in a circle with a flying "duck?" in the center. Left side of barrel "Made In U.S.A." Right side "Smokless Powder Steel". Inside of fore stock is stamped the serial number with two overlapping capital R's lighter stamped over the serial number. Thanks in advance.