What clues do you want? The central core is still there, though you wouldn`t know it as your vehicle climbs to the top floor. The Omnimover elevator is still there, the TT briefing rooms are raised above the original ground level height of holding though in the same place as the original load, and the TransCenter backstage south area is still intact layout-wise.
Aside from that, all physical traces of the attraction itself were removed. The TT briefing rooms are half on the old hold area, half on the old load track. The current queue after briefing uses the old Omni ride mechanical space, and Test Tracks load/unload is exactly on the old unload track. VIP lounge access is also the same as 1982, through the lounge itself was reconfigured to be more employee and less corporate orientated.