To say what Ash said differently; which i hope is helpful.
There is non magical masterwork armor, it gives non magical bonuses. (It has been a few months since playing 4e so forgive me if I am slightly incorrect)
I don't remember reading that you needed magic to create the masterwork armor.
Now on to my thoughts on non magical hide armors;
I think it could be done to have say a non magical dragon scale armor, but what a waste of resources for a pc.
An armorer or supplier would still have to kill a dragon to get it, then have the resulting armor be worth less than +1 magical would be annoying.
The masterwork non magical bonuses are not figured in to attack that ignore normal defenses and you may need magical defenses against some attacks.
If i had the hide I would not make it non magical, I would quest for whatever it took for the magical version.
It is your campaign so do what you think is best, if it makes sense in your world and it is fun, do it.
Game over man... Game over! -- Pvt. Hudson