Those must have been remarkably small armies he cooked. No wonder King Torrhen knelt, how many men could he possibly have fielded? Two dozen?
I begun writing an extensive expose on the forging of the throne in relation to the building of the Red Keep, then I discovered that medieval threadwheel cranes could lift up to 3000kg per operator, making my hypothesis collapse. Just keep in mind, though, that Aegon would not have begun forging the throne until way after the end of his wars. Unless he had been planning to collect the swords of the highborn dead all the way from Dragonstone, it is doubtless he would have them. He could, of course, ask his vassals for their swords, but that's not only awkward but also incredibly insulting.