Type 38 Stock Question

So, someone I know recently came across a Type 38 Arisaka, but has a question about it. The thing is a mismatch, and pretty beat up, the bore looks good, but someone decided to Parkerize it after the war sometime, likely attempting to "refinish" it. The Mum has been worn off as well, and the marks from that refinished over with the Parkerization. The main question arises from the stock. It's beat to hell, but that's not the problem, every image of a T38 I've seen has a small groove out of the stock, just underneath the sight usually, like this:
https://www.milsurps.com/images/impo...3/japan1-1.jpg

The issue is, this one hasn't got that groove.
https://www.milsurps.com/images/impo...3/PLkdGh-1.jpg
As you can see in that cellphone image, it hasn't got the groove where it normally is, in fact, it hasn't got it at all. The stock also has no discernible markings to tell where it's from, no letters, stamps, nothing. The question is; is the lack of the groove some sort of rarity, is it a last-ditch stock mismatched to a Series 24 T38, did someone have this stock made for them when they got back to wherever from Japan, or were there just some stocks not made with the groove in them?

Any help would be appreciated.

We took the thing apart today for the first time, and deduced the stock must have either been made in someone's garage, or somewhere in Vietnam/China/Korea during one of those wars. Not only is it missing that groove, it's missing the hole for the cleaning rod, and a front spring to hold some of the metal onto the wood. There's dirt and some rust and pitting all across the metal, and it appears the Parkerization wasn't a complete process, they only did the visible part of the receiver and chamber part of the barrel, the rest of the barrel and whole underside is blued, which has faded and rusted through in some places, and appears to be scratched in others. The bore looked good when inspecting it, which makes me think this wasn't cared for properly, but also wasn't fired often. It should fire fairly well after a good cleanup, and look a fair bit better, and a "new" stock will probably be in this gun's future sometime.