You're right maddafinga, that bump is the transmission housing. (the nose of the M7 isn't the transmission housing as it's often called, but houses the steering brakes and differential). As stated, it would be OD. Manufacturers recieved trannies painted in both white and OD as per thier orders. HOWEVER! It could be white if it were replaced in the field, so again, another option!
Have fun, sounds like you're doing a good job.
Ron