Data point of one - and I didn’t spend a lot of time on the project.
The Magpul package comes with the trigger guard / well, and one magazine. The trigger guard is slightly oversized, the magazine release paddle is metal, and seems to work well for me.
I looked at adding one to a short action BDL - it was not a drop in as I had expected. I would have had to inlet the stock and trim the ends of the Magpul guard/well to get it in, and it appeared that I may have to open up the sides of the magazine box as well. I’m pretty certain the factory receiver bolts would have worked, and I don’t recall the Magpul package including any bolts.
The BDL metal was working, so I didn’t go any further.
My opinion - they are set up to drop in the Magpul stocks, and can modified for BDLs, but are not a drop in.
Last edited by AH64guy; 01/24/20.