Rifles stamped 53, 54, 55 or 56 are usually replacement receivers that were used by weapons techs (armourers) to repair rifles with defective, damaged or worn receivers. These were new spare receivers from the 1950 production run. They were stamped 195 and the armourer stamped the last digit to show the year the repair was done, that is why the fourth digit on those rifles is often not in line with the other three, or of a different size or font. The armourer then stamped on the wrist the serial number of the rifle being repaired, thus explaining why these rifles usually have serial numbers that mostly belong to 1941-1945 production, including a few British and Savage serial numbers. I have seen these new spare receivers for myself, and if you don’t believe me, there is a chapter in a 1950's Canadian military armourer's manual that outlines the stamping and serialization procedure when replacing such a receiver.