Sure, but MDF is veneered all the time

As a furniture/cabinetmeker, I woudl guess the stand is MDF. Vereered ply may be a bit stronger but it is almost never flat, its more costly and a much bigger PITA to work and finish, especially considering the color finished edges of the ADA stands.
Man, hype/shmype. Now we really are sarting to worry to much about the lure of Amano. If its ADA is obviously made well enough you don't need to worry about your aquarium falling down. Aside from that, MDF, Ply, Veneer or paint grade, its all the same. The outside is the color you see in photos and the inside is apparently veneered. Neither is really a selling point nor a drawback or an indication of quality.
If the outside looks appealing to you, buy it.
(BTW, thats not a slam ar Greg or anyone else, promise)