I contacted the Winchester Arms Collector organization. I was told that These model guns were not reproduced in Japan. According to their search of the serial number, it is an original made in 1903 and has probably been refinished and re-blued. This gun does not have a safety, indicating that it is one of the very first guns made in 1903. I have confirmed that it requires Winchester 22 Automatic ammo. 22 Long Rifle ammo will not cycle in the gun. I have compared the markings on the barrel to pictures of other model 1903 and model 03 guns. My gun is marked the same but is in very good condition. The caliber is "Winchester .22 Automatic" as marked on the barrel.
When I was bidding on the gun, I assumed that it was a new condition Japanese gun made around 1990. I was told that Winchester did reissue some of the old guns made by Miroku, but both Winchester and the collector organization said they did not reproduce the Model 03 or the Model 1903.
The Winchester Model 63 is chambered in .22 Long Rifle, but the big difference is that the but plate is flat and not curved like the Model 03 and Model 1903.
The estate that the gun came from contained a number of collectible Winchesters. I am still not sure what I have got, but if I can find some ammo, I will shot it some and then put it away in the safe.