I was there at ILM with George in the 70's when these ships were being built, i definately remember him saying it was a small military escort ship that had been modified to smuggle, thats why he made sure the modelers used tanks in the construction. The use of F1 Parts was to give the look of Speed. The mandibles toe in because it was meant to resemble chopsticks for picking objects up, George had a love of Samurai and wanted the Falcon to look Japanese and Exotic. Did you know the cockpit idea originally came from a Banana pushed into the model? Originally the Falcon was inspired by Picasso's Paintings, it was supposed to fly vertically so the cockpit was a cylops eye, from the back the engine resembled a butt crack and the Satelite dish was a breast, the mandibles arms.
Another little know fact is that i just made aaaall that up! :lol Its Star Wars, it doesnt have to make sense, but im sure we will see more of the Falcons Origins in the Han Solo Film.