Yet another update:
Guinness World Records Reinstates Billy Mitchell's Donkey Kong High Scores
Statement from Guinness can be found here
I wonder if they truly did any actual research into those cheating allegations before they did this, or if they just caved to get his lawsuit off their backs..........
EDIT: According to Ars Technica, a representative from Twin Galaxies had this to say:
(I am not making this up..........)