The S/N is 5,850,558 which is a 1955 production date. The barrel is a Springfield with a mark of 4-1955 so it matches the action. There is a proof mark circled P from Springfield. There is a cartouche of 3-stars over an eagle which is from the CMP. The sling looks like a date of 1958. The photo of the card is an independent grading that came with the rifle.