@robtrench, here's a hi-res snap of Agent Coulson's memorabilia shelf from last night's 4th episode of AGENTS OF S.H.I.E.L.D. (no, I do not consider this any kind of "spoiler"), which seems to have been assembled for the specific purpose of having fans look over it for clues about... whatever. Click it for the full-size and have at it, kiddies.
It's funny, I was joking in week 2 when I floated my crazy fanboy theory that "the twist" with Coulson might be that he's actually been Jim Hammond all along... but some of this stuff does look pretty old and random. Those two stone tablets are certainly interesting, anybody recognize them (or what era that pilot's helmet might be from?