How old is this Model 10?

I've seen somewhere online that it's actually pre model 10, but I'm not sure exactly how old. Here's the gun. The serial number is S 977466. I'm also wondering what the engraving on the side of this Model 10 Victory means. It's a little hard to read but it says "US 2000-94-150." It was given to my great-grandfather when he was a guard at the Bell Bomber plant around WW2.