Thanks. I counted four along the back, and none below the tailights. My car seems to be a mechanical abberation (i.e. 7 bolts on front bumper instead of six; 3 bolts on the radiator fan instead of 4; six bolts on the PS steering pump instead of 4; no exhaust manifold obstruction over the idler arm bushing, etc.)
I'll wait and see your photos since I am sure I missed something. Unless there is some sort of inner track the ends of the bumper ride on, I am doubtful that the 4 bolts I see are all there is. I pulled back the liner under the tail lights partially, but not entirely, so I probably missed what was there. I did notice, however, that the bumper mounting bracket did not extend to the tail lights, so any bolts that are there must be attached to a secondary bracket -- much like the front bumper edges.
2001 E430 4matic
Gone but not Forgotten:
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black