[Runequest] Medieval Tech Levels

[royce at efn.org]

Greetings, All,
   I've been contemplating the weapons list and the year 1300 AD.  It
seems to make an a difference if I set a Europe-centered campaign prior
to the Late Middle Ages -- or to a technologically equivalent fantasy
realm.  From the 1300's onwards, we get platemail -- and a variety of
weapons that developed in parallel with it.  (In response to
platemail?)
   I recently read that the bastard sword (or something very like it)
first appeared around 1250, and that the first records of English long
bows in battle are from around the 1280's or 1290's.  I am
contemplating that era as a cut-off date; to keep those two weapons,
yet exclude the Late Middle Ages.
   Any thoughts or reactions?  Am I missing something significant?  (Given
my weak grasp of medieval history, I'm probably missing a great deal.) 
Your thoughts & suggestions & observations would be most welcome.
   Sincerely,
Asher