After cleaning the cam towers up, I notice only one has a bearing, oddly the same one where the was none in the cam saddle.

MBZ 606 uses only a half shell bearing???

Its not like I have 6 bearing shells laying around the parts tray!

What gives? Thank you! there is NO mention of this in the FSM, and I've searched here... but I'm trying again...

In the 210 FSM for the 606.912, there is no mention of bearing inserts on the camshaft housing or the bearing caps.

Were the bearings that you found on the caps or the housing? I don't see why you would need them on the housing since the camshaft is pushing down on the lifters (right?). Also, since neither is cast into the head, you could replace the housing and the caps if needed.