The Ciussi Inox stainless cage has red buttons, the yellow buttons were on the original alloy Ciussi. The Elite 3c cage (also called the Ciussi 'Black' by the company) looks very much like the original and has yellow buttons too but is only available anodized black.
Originally Oscar Egg's company, produced all sort of kit (mainly rear mechs) under the Super Champion branding. Eventually owned by Wolber and then passed on (complete with the remains of that company) to Hutchinson.
From the way it follows the line of the joint I'd put money on it being cracked braze filler though there's a small chance that it's just the paint if the joint wasn't cleaned properly before the frame was painted. Not difficult to fix.
A standard outer cable slides through the tube on my FCK9. Unlike the dural frames, the seat post is 23mm. Although stamped VITUS, I believe it's actually a Stronglight Delta post. I maybe picky about it, but whosoever made it, it isn't great - before I corrected it, the 'aero' section on mine...
I used to ride 177.5 then dropped to 175 when I started riding again because at the time there weren't any longer cranks immediately available. My new build has a set of 180 waiting to be mounted once the frame has been refinished.
I vaguely remember one day in late 81 or early 82 a box van arrived at the Falcon factory in Brigg with the contents of the Quinn workshop - including a couple (or more) Quinn frames - which were all stacked in a corner of the little used 'showroom'. I moved on a month or two later so have no...