AboveTopSecret "A Boeing 757 struck the Pentagon" post says "More parts from inside the 757 - note the Boeing green primer on 3 parts in this photo - two circled".
debris lying outside the C-ring punchout hole in A-E Drive included a chunk of nose fuselage or nose cone, a landing gear, and an aircraft tire tread.The following photo (by Fort Belvoir photographers) shows two pieces of fuselage debris (note the green primer) lying in front of the hole. Note a ring of 8 small holes on the larger piece. A similar ring of 8 holes may be found on a 757 nose (with an attaching piece), just below the cockpit windows -- but it is far from clear whether the configuration is a match. This larger piece of debris may be the fragment of "nose cone" referred to by Lt. Kevin Shaeffer and Victor Correa
Although partly disputed at Pentagon Research: http://www.pentagonresearch.com/exit.html