The early Model Gs companion white wall brush had the classic metal holder with the aqua brush plate (circa 1960-64). Later ones had the plastic holder with the teal trim (as stated in reply #19):
Here's another photo of the one in reply #17. I do wonder if the teal Model 1205 paint was identical to that of the teal Model L (although it doesn't appear so to me--the 1205 looks metallic). In that case, I would call this a teal Model L version.
To my knowledge the Model 1401/Super J version with the gold brush plate was the last white wall brush Electrolux made (1975-78)--going by the manual. Interestingly, the same ivory holder with teal bumper that came out with the late aqua Model Gs was used. I have not read an Olympia One manual to confirm that the white wall brushes had been discontinued at that time (nor have I seen a white wall brush with a brown brush plate). Of course, branches could carried old stock after 1978.
Just to update this - the white brushes must have been around until the Silverado was out as I have come across this picture of them and have actually managed to get one of the dusting brushes.