Knowing if you have AutoCAD or a vertical product can make a world of difference in troubleshooting or support such as what service pack it requires.
Is it really AutoCAD or Autodesk Architectural Desktop . Vertical products all make changes and additions that make it completely separate from plain AutoCAD. It is common and an understandable confusion but under the hood to hear someone says they are using AutoCAD but are really using Architectural Desktop. So please when discussing the product you use in discussion forums, support calls, or with other people, please make sure to mention exactly what product you are using.
AutoCAD vertical based products:
Autodesk Architectural Desktop
Autodesk Building Systems
Autodesk Civil 3D
Autodesk Land Desktop
Autodesk Map 3D