Spot on with your diagnosis. Not an uncommon problem with (usually German) lenses from a few years back, causes by the failure of the balsam cement holding the elements together. The good news is that the lens will be still entirely useable, the problem is mostly cosmetic, can cause a slight loss of contrast or flare, which shouldn't show with an enlarging lens.
I have a Tele Rollei where the separation covers nearly all the lens, and a Voigtlander Septon that is about half affected, both lenses still take great photos, so I wouldn't worry about your Componon....which is an excellent optic BTW.
Tony