Get ClassID of different versions of program with same ProgID

[Matimus]

Bummer you can't look into the registry. By convention the ProgID is
named <Program>.<Component>.<version>. Also, usually there is a
version independent ProgID that goes <Program>.<Component>. The
version independent ProgID usually points to the newest version. It
looks like that is what you are using. Many programs get away with not
using those conventions, but I'm willing to bet that there is an
'AutoCAD.Application.14' and an 'AutoCAD.Application.??'. I don't know
what will be there for 2004. Chances are that it is not '2004', but
'15'  (or something similar). So, you should be able to use those
instead of the version independent one.

Matt