The two little screws just hold the top of the stock to the riser and just need to be snug. If you have one that is binding it is probably because the hole in the riser is not aligning with the hole in the stock and it is binding. You can open up the hole in the stock with a slightly larger drill bit to give more room and that will help to allow the screw to go down further. It is a minor issue but nothing that could not be fixedvery easily...
Wyvern