This is a remanufactured / refurbished / rebuilt, OEM GM brake master cylinder for 1963 Chevrolet Corvette C3 vehicles. I removed this from my survivor 1963 Corvette and sent it to Lonestar Caliper Co. to be rebuilt. It has a reproduction cap that was provided by Lonestar. My opinion is the date reads "M292" but you can judge yourself from the photos

GM Part # 5462389