I think it's a Sheraton, probably a Sheraton 15. I've never seen an Empire or Sheraton 12 with preset pistons between the manuals. In addition, every Empire I've seen -- including mine -- has only two animation tabs, about 3/4 of the way across from left to right. On Sheratons I've seen both two and four. (The one in the picture has four.)
But this is all anecdotal... I've only ever seen 3 or 4 Empires at all!