As noted above, the pictures may differ as well depending upon whether the letters are small or large. For example, Cobb's pins have pictures of him with the D on hat (small letter pin) and without the D (large letters).
And the pins can really be expensive too (at least in the minds of the sellers who don't inhabit planet Earth):
http://cgi.ebay.com/1910-P2-Sweet-Ca...item3ca94dd337