Re-use M117 Headbolts?
 

Are these TTY(torque to yield) type bolts? I'm referring to the head bolts that are also cam tower bolts.

The service manual makes no mention of the need to replace head bolts, so they should be OK to reuse. Mine were reused 16,000 miles ago, and the cam towers were off on the LH side once. No problems with head gasket sealing. Normally TTY bolts are characterized by angle torquing (i.e. 20Nm, then 90°).

Have fun getting the left rear long cam tower bolt out. Looks like the brake booster would have to come out.