Matte, ship 25/02.
After waiting on the 17" for the little larger screen, I do not know, but yes, there is a good chance that I would go with a 15.4" matte, if I had the option.
If Apple would come with a 15.4" matte option, it would make a group of buyers alittle unhappy, cause some, like me, would probably have bought the 15.4" then, rather then wait for the 17" with matte option. My bet is that the chances of a matte option on the 15.4" are very low.
My point being that if it was to be the case, then Apple might have added this option along with the 17" launch.
Why not to do so would be to anger those, if any, unhappy glossy 15.4" buyers who would have prefered the matte, solution for the matte missing option on 15.4" would be a matte film cover.
So yes there is a matte option for the 15.4", but not from Apple.
Be happy about your 17" matte, and if you went for the 15.4" glossy, matte film cover is always an option of a kind.