Hey Codiaz! It's nice to see you are enjoying playing CoD4 on our servers! (:
However, it is actually against our rules to wear the =FA= tags while playing, unless you are a trial member+.
That information can be found here (rule #11).
If you are interested in joining F|A, please read the relevant wiki pages and check out THIS page on how to join our community.
If you continue to be an active member on our forums as well as a responsible player in-game, your chances of being accepted (and chances of getting to wear those tags!) will be much higher.
If you have any questions about our community, how to apply to become a member, or anything else, please feel free to contact me.