Matt Light is probably one of the few LTs in the league who would be almost useless as a RT. RTs are generally much larger, and much more powerful, as are the defensive ends they face.
Light at RT would be like watching Light against Aaron Shobel every week.
Light usually does well against the bigger DE's in the league. Its the small quick de's he has trouble with.
Schobel is only 245-250, Freeney goes about 260. Mathis is about 245 as well.