Quoted from TigerLaw:The art means the backglass and the sides . . . not the playfield (at least that is how Stern has always treated it when they say custom art . . . the playfield is always the same art package).
They do use different playfields between the PRO and LE/Premium games and at least once with a significant difference in art.
Angus Face/Window on ACDC
Light up inserts on Regognizer and Silver Ink on LE TRON
Metallica Window in Coffin and hole for disappearing Magnet.
But yes, usually the art is 99% the same between the games, but I think they are going to have to do it very different for this LE. Especially if the are going to add a spinning disc to the lower pf.