There's several different variations to the names, which can lead to thinking that the name list is old, when it's actually just current and VERY dynamic:
First part:
a. Just the name
b. the name with Lord/Lady (if you've currently got it)
c. Your name with the full reputation title
Second part (it can be any of these, regardless of which ones you have displayed):
d. no second part
e. Your guild abbreviation
f. Your Champ title
g. Your mouse-over overhead profession title
h. Your paperdoll's profession title
i-k. = e, plus f, g or h.
I've seen just about every combination of a, b or c, combined with one of d-k, on the small and large pumpkins, and 3 or 4 of the same combos on the jack o lanterns. I've not (yet, at least) seen any with Guild titles on them.
They appear only spawn with your name while the character is LOGGED IN, though you might already be logged out by the time your jack o lantern is discovered. For a while on LA last night, we were getting worried, as initially 90% of the pumpkins in Trammel were from PvP guilds - then we realized there must have been something going on with them in Fel, so their numbers were inflated.