[Arran]

There are several different species and what they call "Cuts" of veneer, from various parts of the tree, each can cause the colour and grain to differ significantly. What they typically liked to use on many radio cabinets was what they called "French Walnut" which is a lighter reddish brown colour, Philco liked to use quarter cut French walnut but also used plain cut. What you may be looking at is North American black walnut which is a greyish brown colour. There is also something called Claro walnut, which I haven't really seen on a radio cabinet, it's sort of between the two. It's best to go look at the gallery of various species and cuts of veneers on the Constantines website as a guide
Regards
Arran