Just inherited this Crosman powermaster 760. It has the ribbed forestock...brass bolt and trigger and is very nice condition and shoots. My dilemma is dating it. I know thru research that it was made 1966-70. And I learned that the serial number is stamped on the barrel ring and should contain 3 numbers? example is 168 which would be Jan. of 1968. My problem is mine is stamped with a 10. Just a 10....any ideas anyone? And does anyone know of the value of the gun? Thanks in advance...Bob