No version of HP-UX has ever achieved a C2 rating although I'm sure it could if HP choose to persue it.
HP-UX BLS 8.04 and HP-UX BLS 9.09 are rated at B1. And yes, the ratings are current. These are the only official ratings that HP-UX has ever held.
HP's proprietary OS, MPE, did have a C2 rating. MPE V/E G.03.04 was rated at C2 but this rating has now expired. This may be what you thinking of.
Also, it's ok to have a higher level of security than is needed. So if NSA wanted a C2 version of UNIX, HP may indeed have sold them HP-UX BLS 9.09. When you hold a B1 rating, you completely meet the requirements for C2.
You can view the list of currently rated products at the
Evaluated Products List. And here is the
Historical EPL.