but does it require me to drill super precise holes next to each hole for the main shaft?
Yes it does.
Not only that but it is a rectangular hole.
What you do is to drill the main hole, slide the pot into it and mark the position of the slot. Either by pressing down and twisting slightly to mark the space or by putting a spot of Prussian blue on the spike to mark the surface.
Then you know where the slot should go drill two 1.5 mm holes at each end and join them with a router or Swiss file.
It is easy enough for plastic and you don’t have to be too precise because the hole is covered by the knob.
Don’t ignore it because it will not mount flat and the mechanical stress will make the pot fail a lot sooner than it otherwise would.
And covered up by the knobs:-
