you know I have seen that setup and was underwhelmed with it's overall look, the stock is just screwed on with 4 small allen screws, I'm guessing 4mm and i can't tell if they are using the same clam shells or new ones with the mounting areas beefed up, thicker, and it looks short
so where to get one, I would try Umarex or PA
installation would be easy, you would need the right tap and drill for the tap
so you got a feel for my opinion but the truth be told it a clumsy looking lash up
they take the front sight off but are too lazy to remove the rear sight and putting on a weaver mount and in saying that the clam shell were not changed
I have a LP 8 and did a complete trigger rebuild so I know the pistol
so who could do the work some one that could take the pistols clam shells off and do the drilling and tapping and that person is unknown to me, maybe Umarex would do it
just my observation, mock up a shoulder stock with the estimated length that that lp8 has and see if it ever works
take care
mike