It's 8 armor.
Quote:
Originally Posted by guildwars.com
Increased the inherent armor level on all unique (green text), promotional, crafted, and collector shields so that they behave the same way as other shields when the characters equipping them do not meet the necessary attribute requirement.
Originally, green and collector shields would give you (I think) 3 armor, while gold shields (I know) gave you 8. They changed it in an update, which is why I have like 3 green shields on my ele (eles can have low energy sets too!)