Found it.
Unfortunately, it doesn't seem to give the info I wanted. I can tell it's Content Server 4 (4.1.2 in fact) so it might have the new DRM enabled, but I can't tell if it has. Sorry.
[EDIT]
No! It's ACS 4.2 that has support for the new DRM. 4.1.2 can't handle the new DRM scheme, so that's not your problem.
I can't think of any reason why (if you had authorised your ADE with your Adobe ID
before opening the .acsm file) that you cannot now open it in ADE 1.7.2 with the same Adobe ID.