From the Clan Wallace Website
The Wallace " Blue"

This tartan is not often seen. The previous Chief, the late Lt. Col. Malcolm Wallace of that Ilk, said when asked about the Wallace Blue, "it is a very nice tartan, but it's not Wallace". Malcolm only recognized the Red Wallace and under duress, the Green.
Emphasis mine...

The Chief pretty much can acknowledge the "official" tartans, but your reference was to the previous Chief of the Wallace Clan, and since they are showing the various tartans on their page, that means they at least acknowledge them, though the "Blue" and the "Wallace of Dundee" are not commonly thought of as "Official Wallace" Tartans.

Todd probably has better information.