If this is the photo you are referring to in the Old Luger Centerfolds... this is a Model 1900 Luger equipped with an Ideal Stock... Ideal being the manufacturer...
The stock is ambidextrious and can be worn on either side as a holster and extends to create a shoulder stock. The gun has to be equipped with matching grips that are made to accept the stock... the stock does not attach to the pistol, but to the grips.
This stock can only legally be attached and use with the model shown... use of any other Luger with this stock/grip combination would be a federal felony of creating a short barreled rifle...
You will find several examples of this stock in the Member Gallery. Do a search in the gallery for "IDEAL" as well as on the lugerforum... you will find all the info you are looking for.
