As cool as it is, I don't know if we could all agree on a single year. Every time you add or remove something, or upgrade a component, you can end up shifting your year by a decade in one direction or the other.
Heh, on the DoK thread on facebook, someone was pointing out narrowing the Hospitaller kit in one of the pics to a specific decade because of a combination of the armor and the black surcoat.
I'm trying to get myself together enough that I can have reasonably period mail that will work with my usual circa-1300 kit, but also work convincingly as a 1250-1300 sort of thing, as a Teutonic knight perhaps (I have the surcoat and cloak on the way now, I decided to try the GDFB versions).
Sometimes getting everyone into the same century is hard enough.