Effective immediately, all syn supporthelps will also receive the canview:entryprops priv as part of their priv package. This priv will permit you to view meta-information about entries by going to this page and pasting in an entry link.
Syn-wise, the useful lines are mostly:
User Date/Time: 2009-02-20 05:00:00 Server Date/Time: 2009-02-20 05:22:49
User date/time is the date and time that were listed in the feed, and server date/time is the time synsuck ran and posted the entry to LJ. syn_id is the GUID or other unique ID that LiveJournal picked up for the entry, and syn_link is the <link> attribute's information. For an outstanding guide to reading entryprops output, check this post to support_interim.
Of course, you're being given the priv to do syn stuff, there may be sensitive information exposed through entryprops, abuse of the tool will you get whomped, etc. etc.