I'm wondering which screws you're looking at.. There are 6 regular screws for the carburetor drains[horizontal] which can be readily seen on the bottom side of the carbs.. There are also 5 screws[also horizontal] under the choke linkage covers which are for slide position adjustment..The pilots are contained in a vertical casting in the fuel bowl housings and are not readily 'seeable'..Now if some one has removed them and cut/slotted them, then maybe that is what you are seeing..
When I Look @ my bike ( carbs on bike) I see the screws in plain sight.
Maybe I need to dissect this bike more.
The Manual seems worthless at least until have bike apart.
I was just trying to learn this Carb stuff on this bike for when the time comes.
I also wanted to learn the resync.
3 of my friends have the gauges to resync
but I don't trust they know what they are doing, based on questions I have asked them.