1) game is out of production, released 5 years ago, so any chances of new additions is close to 0
2) game tries to follow history within limits of the gameplay, so you need to check the source material for which era certain things belong. Game world is 9th century, year 868 or so.
3) you can visit the modding section and/or Forge and add things like shields yourself (it is not hard). Modding allows you to chance pretty much anything you want with the game, from how it plays to how it looks (within the limits of the engine tech, of course). Try it out if you never did