[Arran]

The control panel on a 90 is always walnut, probably French walnut, the cut used probably varied, and what part of the walnut tree used probably varied as well. The 70 front panels can be either ribbon mahogany or French walnut, though the veneer looks like quarter sawed french walnut as the grain is straight much like the ribbon mahogany. If in doubt as to which cabinet is which the 90s always have feet cut out of the molding on the front corners, the 70s always have a straight molding with no feet. I don't know about the grille cutouts, the first example does not look like it has a a 1/4 round profile around the edges where most I have seen do, even my model 60L had this.
Regards
Arran