While they won't make you draw the actual schematic, they may ask you to draw the synoptic page on the RJ if you flew it. SkyWest is very against learning from actual schematics all throughout training. On the RJ we use the EICAS synoptic pages ase a reference. If the most complex system you have flown is not the RJ you still wont have to draw the actual schematic. They just want to see that you have some techinical knowledge of the aircraft you flew. A drawing with boxes that represents something would be fine. As long as you can explain how what those boxes are representing works.