I have the seals that go around the "special knock pins" accounted for, and anything else remotely "o-ringish". The little rubber inserts I refer to are solid and have a small protrusion at each end. I just popped out one of the white "spacers" from between the fins and sure enough, that's the part I was worried about. The cylinder parts drawing calls for 20 of them, the head drawing calls for 2 more. I believe wrenchmuch nailed it.
Rob