I make sure the slot in my tang bolt is lined up with the barrel. With the cheek weld I use; I can see the slot in the tang bolt and the front sight. The aiming procedure for most fowling guns requires being able to see the entire front sight, some of the barrel and the slot in the tang bolt to properly point the fowling gun. With practice, the cheek weld and alignment becomes a natural action and conscious alignment is no longer necessary.
Note the alignment of the slot in the tang bolt just behind the breech. Admittedly having the groove means that you don't have to take care to ensure the slot is aligned.