I got this shot gun from my dad about 20 years ago. As far as I can tell the barrel is not cut down but the rear stock has been cut down. The finish is all gone when I got it I just tried to keep the rust down.
On one side it says 410 three inch chamber M8Ideal (kinda hard to see)
Other side has half a letter and 2 numbers Maybe M68 Japan
The hammer top has been rebuilt before my dad got it. The barrel is just over 19" long and over all is 26.5" so its legal from what I can find