I was looking at Wowpedia's WoD list of Garrison APIs, and discovered most of them aren't documented. I know, or can find, the bodyguard followerIDs, and I don't care about followers for other buildings, just the Barracks, and only when a follower is assigned who can gain reputation. Therefore, Barracks ranks 2 and 3.
However, what I can't figure out is how to determine if a bodyguard is assigned during login, or if a bodyguard is added or removed during gameplay.
Any nudges in the correct direction would be appreciated, thank you.
I remembered the old LibBodyGuardHealth-1.0 project, and took a look at its code. The part that is useful to me is the local function UpdateFromGarrison() which starts on line 247 in the file I downloaded.