Of course check for cabinet fade, particularly the eagle on the cabinet front (most are faded here it seems); also check for fade on the yellows/browns on the sides. (IPDB has some unfaded/faded examples.)
Make sure the topper is present ($$$) and also check for fade on it, too. Most will have a bubble or two in the foil.
Mountains are often cracked as well.
Just about all of them have Lost Mine Kickout wear; LSOG sells an overlay.