Question for model 53 owners. Have a N.O.S. barrel 8 3/8th has same front site as a M-53 has same shrouded ejector rod as a M-53. It says ".22 Magnum" on the side of the barrel, and is for a K-frame. Is the M-53 on a K or N frame? What does a M-53 say on the side of the barrel as a designation?