C-clips or circlips are the positive back stop for BB30 bearings. The reason they exist is...alignment...without circlips, the bearings are more prone to cock. Further the circlip acts as a wall to control spacing between bearings...without, bearings can press in a bit too far because insert diameter between bearing bores is deliberately large to keep weight down.
First things first. You don't have to remove the bearings to determine if the circlips are in place. With crank out, you can peer through the bearing inner race bore and see the backside of the opposing bearing. If you don't see the circlip on th backside of the opposing bearing with flash light...do NOT install the crank. Get some circlips and knock the bearings out and install them with circlip pliers. Very easy. Press bearings back in with loctite...clean with alcohol or adhesion promoter prior to applying loctite and pushing back in bearings.
Red cranks use a wave washer with spacers. Once bearings are properly installed, you should use the correct amount of spacers to place the wave washer in the middle of its compression when the left arm is fully attached.
Hope that helps.