The point I was going for was that, although a few extant anomalies have come to light, I don't think it's correct to state that generally "there was also an overall gloss transparent brown called Walnut at that time"
if we are referring to colour availability. If we were to include all one-offs, custom orders, mistakes, factory seconds, protoypes, test runs, etc, then the concept of colour availability would have no meaning - we would instead be saying that any colour was technically an option.
To highlight my point, I, for one would not say that 360WB, Wide Neck, Gun Metal Blue was factory available in 2010, even though there's one on the Bay right this instant!
The reason is that the term 'available' has limited meaning is this instance, just as I believe it does with non-burst walnuts, or any of the other Rickenbacker anomalies that we've seen on this forum.
To sum up, I believe there have been five officially available Rickenbacker browns, all of which have been burst finishes;
50s Two-tone brown, as shown here
. Glossy, and dark as dark as dark can be.
50s AutumnGlo, as shown here
. Replacing Two-tone brown (Are these the same colour re-badged? JH, anyone?...)
70s/80s Walnut, as shown here
. Glossy, and usually lighter than 50s AutumnGlo or Two-tone brown, though many variations in darkness/lightness of the brown.
70s/80s AutumnGlo as shown here
. Exactly the same colour as 70s/80s Walnut, though in a satin finish
. As with Walnut, many variations in darkness/lightness of the brown.
03/04 Montezuma Brown, as shown here
. Glossy, and darker than 70's Walnut.
In addition to the five officially available colours above, there have been noted examples of non-burst Walnuts (usually from the 70s) as shown here
, and very dark FireGlos (usually from the 60s) as shown here
Two wrongs don't make a right, but three rights do make a left.