The grind is totally different at all points.
Traditional tanto/aikuchi = Full flat-grind with zero-bevel edge (often convex), sometimes with fuller, with a soft continuous slope from point to belly.
American tanto = Saber and/or hollow-ground with bevelled edge, and a sharply angular transition between point and belly.
The outline is inspired by the traditional tanto, but otherwise they are totally different IMO. Don't get me wrong, I think the Lum design, especially the fixed blade, is beautiful. But it is not much like the tantos I've seen displayed in museums.