So there is an oil leak coming from the bottom of the barrels around where the oil breather dowel is. After taking the barrels off the gasket is nackerd and seems to be split where the dowel is (pic 1 and 2) so I'm thinking that could be the reason for the leak.
Now for the sense check. After having a look at the CB400 four engine rebuild that Nurse Julie posted it seems like the little o-rings that go around the dowels werent there (pic 3). So it seems to be a combination of both the gasket and the o-ring. I plan on replacing the gasket, obviously, but couldnt find the little o-rings for the dowels on davidsilvers, unless I missed them. Could someone point me towards them? They definitely should have the o-rings for the dowels right? I couldnt find any mention of the o-rings in part diapgrams I've been looking at.