THS, some truth in the ideas. F3/F6 era squadron aircraft were used for aeros, thus generally they would retain the missiles.
The older dedicated F1 areos aircraft (some with smoke mod) were reported easier to manoeuvre with missile pack pylon stubs (winglets), no missiles, particularly for inverted passes. There may also have been a cg effect without missiles, aft cg being more manoeuvrable, and less drag, but retaining lift from the pylons.