GRS recommends to glass bed all our laminate rifles stocks (Except Sauer 202). The inlet is precisely made with CNC machines, and most models are drop in but we recommend glass bedding non the less.
In our experience you will get better accuracy by glass bedding the action to the stock, therefore we recommend to do so. Eliminating any possibility of bad accuracy is the name of the game.
The top three inlets are made to fit the original pillar bedding blocks. These are not provided by GRS, so you need to get a new pair from your local distributor, or use the ones that is in the original stock. The Blaser R8 and R93 stocks are made for the "professional" inlets (not the two piece). These need to be glass bedded in the rear of the action where recoil is absorbed.
Any question, please ask your local GRS dealer.