https://thegreatmodel8.net/

JUST A QUICK QUESTION FOR ALL OF THE KRIEGER OWNERS OUT THERE -- THE ONE I JUST PICKED UP HAS A SERIAL NUMBER STAMPED ON THE MAGAZINE THAT MATCHES THE GUN AND I WAS WONDERING IF ALL KRIEGER MAGAZINES WERE MARKED THE SAME AS THIS ONE ???

Once upon a time Remington serial numbered the magazine to the gun, perhaps this is what you're seeing. This would be especially true if it's an early - mid production Model 8.