Did you take the bolt apart and check the number on the end of the safety knob? I still can't imagine that being correct for that rifle. Unless someone tried to polish it up while they were drilling extra holes in the receiver.

I can't find my Japnese Rifle book, been missing for about 2 months, starting to fear I left it somewhere. I do have a second one but it doesn't show the detail of the safety knob. I believe it should be grooved however.