Yep, RC = Regular Carbine. Marlin hasn't used that designation in years so it must be an older gun. 1948 to sometime in the 60s.
It has dice embedded in the butt of the gun.
Are you referring to the round white plastic bit with the black dot in the center on the bottom edge of the butt stock? If so, that a Marlin trademark called the "Bullseye" which has been used on walnut stocks since the 1920s.