I pulled out my Type I and everything looks the same with the exception of the small groove on the right side where the safety button goes on the bolt when closed. On yours it is rounded, on mine it is more sharply cut in the front.

I can't tell from your photos but does it have the split butt stock? Type I's have that just like the Type 99's.

You shouldn't have too much trouble getting a barreled action. They aren't as common as a Type 38 but they are around and inexpensive. They make for a very heavy rifle.