Ron,
I just noticed that the screws holding the attaching iron extend both above and below the iron in the photo... I have not seen a representative of this type of stock up close... only this photo. I have another example photo somewhere from the same source, but my unorganized collection of photos has grown so large that it is difficult to find things at times. Perhaps someone who owns an example of this type of Luger and stock could comment and post additional photos...
Notice the distinctive Finnish front sight on the Luger as well...
To me, the stock in the photo looks to have been harshly sanded to remove the dirt of ages of storage and use... the holster isn't in such great shape either... but I still wish it were mine