The B7 came in three colors:
— white & gray (matched the Model F, 1959)
— chromeplated (special award model, 1959)
— light turquoise (matched the Model G, 1960)
The B8 came in five colors:
— light turquoise (matched Model G, 1961)
— dark turquoise (matched the 1205, 1968)
— gold (matched the Golden Jubilee, 1974)
— brown (matched the Olympia, 1978)
— slate gray (matched the Silverado, 1982)
I've never seen a B8 in any other color. I'm pretty sure the slate gray color was carried from the Silverado through the 1521 series (1984-88) until the plastic Diplomat came out in 1989 and a new plastic floor polisher - rug beautifier came out with it.
Thereafter, Electrolux made plastic-body machines that are lighter in weight. Which, with a floor polisher, is not a good thing. The newer models are nowhere nearly as fast or efficient as the older "cast iron" machines.