Indeed you need either a EVO386 24 R or EVO386 24 C, the difference is that C is better protected against moisture and dirt.
No real disadvantage to use EVO386 24 C, it still runs better than standard bearings and last longer than EVO386 24 R
The bearings sit in a aluminium housing that is pressed into the frame, no spacers or adaptors required. No creaking and flex. Optimal stability and power transfer. The R-version is the bearing which has less friction than the Cyclocross version.