1) FAQ #64 predates
2) The same user (and me too) was confused about why the public can no longer view other users' moodthemes. I dug through CVS and found an lj_dev post where it was discussed. As of David's Dec. 4, 2003 patch, the 'ownerid' GET argument must match the owner of the specified moodthemeid for other users to be able to view it, so it's harder for bots to spider. I'm not sure if it was decided this shouldn't make it into FAQs or what, but just a quick heads up.
A quick disclaimer: If this has already been discussed before or something and I didn't notice, sorry. I don't read this community very often. :-/