As mentioned in another post regarding head gasket details, I'm doing the head gasket on an M103 (1991 300E 2.6). There are a few small details I could use some info on if anyone can help.

First, when buying the tons of parts I'm replacing, one of the items I got was a "Timing cover O-ring". In disassembly I came across no such O-ring. Unless it fell to the ground without notice. The only place I see where it might go is in a bolt hole wit an expanded opening on the lower timing cover where the fan pulley bracket bolts to the front of it. It isn't mentioned in my Haynes manual. Anybody familiar where exactly this O-ring goes?

Second, Is there a torque spec for the three small bolts that hold down the oil rail? Should I be particularly concerned about them rattling loose (ie: use threadlock on them or slightly blunt the threads)? Same with the philips screws that hold the baffle to the top of the valve cover.

Thanks for any help!