iT looks more like my two 135mm Componons than my 135mm Componon S, so yours is a very early S version.. It's mounted on a tube I think, I was given two Durst turrets full of lenses about 12 years ago and the Componon S had a rear tube that unscrews from the lens barrel.
All the other Schneider (Durst) lenses on the turrets had conical spacers and were fitted to tubes threaded inside and out (39mm) the turrets were from roll-head colour printers were focus was fixed and enlargements are made by changing focal length. The double threaded tubes allowed focus to be set accurately these were then locked by grub screws.
So that tube needs unscrewing before the rear elements can be unscrewed, front elements should also unscrew,
Ian