An easter-egg in Firefly's pilot episode reveals that it takes place in the same universe as the Alien series. It appears the anti-aircraft cannon Mal uses to shoot down an Alliance fighter was manufactured by Weyland-Yutani Corp.
So does this mean Weyland-Yutani provided the Browncoats with weapons to fight the Alliance? Whose side do you think they were on in the Unification War?
The people at Quantum Mechanix were invited to Universal Studios where they got to see the model used for the crash scene in "Serenity." While there were rumors about the movie using a simple styrofoam model, the real thing is about as far from that as you can get.