I have in my collection a handful of Automatic Binding Bricks, the ones that pre-date the 1958 Lego brick.  They are red, yellow, green, blue, and white.  I recall seeing images of these bricks in medium blue in the original Lego Book (the 2000 edition) and other sources.  None of mine are this color and I've never seen them in real life.  Does anyone know if this is a real color for the pre-Lego bricks, or is it that the ones in the images have faded over time?  Medium Blue is my favorite Lego color and I'd like to find some.  But I don't want to go on a search if they don't exist naturally.  Any help would be appreciated.  Thanks!