Looking at fr34olivier's image and his interpretation of what they mean, I don't see it that way, almost the reverse.
The reason I say that is, assuming that fr34olivier is correct, then there isn't a consistency throughout the AMS. If you check the AMS, Settings, Connection type, those with the inverted Orange triangle and black box with White text are the connections allowed for updates.
I for a time only had the WiFi connection type allowed and I was getting avast updates, so if it meant that WiFi updates were disabled and 3G and Roaming updates were allowed I would have seen this in by Data traffic and Telephone billing (I didn't see that).
So either we're both right, in which case there is inconsistency in the icon meaning.
Or one of our interpretations is wrong.
I currently can't test as my pone isn't rooted, so the firewall is disabled and the listing of apps all have three greyed out boxes to their right.
####
Black box, White text/icon and Orange inverted triangle, connection method enabled.
Grey Box, White text/icon and NO Orange inverted triangle, connection method disabled.