award tickets do not credit the $5, I think the T&C specifically say that award reservations do not qualify. i have never received credit for award travel.
http://pss.united.com/web/en-US/apps...onditions.aspx
as for the FareLock, I am not certain, but I would guess that it's the time of ticketing, so if you sign up for ua.com club during farelock but before the actual purchase you should get credit. it's definitely an arguable point to get retroactive credit if it doesn't post.
also, one pain is split itineraries, you almost always have to email in to request the credit for anyone split off the original PNR. they always credit, but it can take weeks if not months to work your way through customer service.