Enlarging lenses - why no lens caps for them?

I have front and rear caps for both my Rodenstock Omegaron and my Schneider Betavaron. The Betavaron came with both, I think the Omegaron are "found" caps. The rear cap has "Omega" silkscreened on it and has a tab sticking out.

Like post no2 My 50mm apo Rodagon has a cap so has my Nikkor 80mm and My elderly Schneider 80mm 5'6 Componon.
Only the front cap though, because they live in a plastic box where they are screwed into a 'molded' keeper after use.