What my point is, is that I think It might be a clue to a future game.(not persay saying the next one.) Now I've already posted my complete idea about this Here
Now since brotherhood has come out, my idea had been blown some hope into. If you're intrested in this make certain you've read my other post mentioned above. Now for this post:
Look how much the image on desmonds shirt resembles the image below rather than an actual eagle. There is no image of the final shirt image as it is in the game. For the pre-release images do actually have an image of an eagle on the shirt. However in this video , It shows the image as it is in the final game. Pause at 3:01 and look how much it resembles This Eagle Warrior You can sort of make out a nose, mouth and chin from the print on desmonds shirt. Also referring to my theory is this article which says AC II might have been in Mayan times
Thanks for your time, kind of a long post srry bout that..