That term is used to. If you don't have it already, there is a book by Solvay Pharmaceuticals called Now That I Have CF and it is geared towards adult diagnosed cases. You can ask you clinic to get it for you. I think the medical info is a little bit outdated but it gives you a general idea of what can happen. It also addresses the issues unique to adult onset of the disease and adult diagnosis, like the emotional impact and financial considerations. I cried my way through parts of it but I felt SO much better to have my concerns addressed.
I think I know what you mean about labeling. When I walk into a new doctor's office and say I have CF I get all kinds of questions. Forget it when I say I was diagnosed at age 36. Even and ENT who sees CF patients said my sinuses don't look like a typical CFers. I get tired of the comments and wish I didn't have to feel like a bug under a magnifying glass. One doc even asked me if my CF will shorten my lifespan. I was pregnant and newly diagnosed at the time and almost cried. Doctors (and pretty much everyone else) just don't know that CF can present like this. If there was a distinction in the name or even calling it "adult onset" maybe there would be a little less confusion and a little more awareness.
I haven't tried to purchase life insurance since my diagnosis. What I wonder is if I will grouped into the category of all CFers with the average lifespan of 37 or if the insurance companies realize that the life expectancy for the mutations I have is thought to be 50-70 or even above. That might be where a differentiation is needed.