Can I have more than 1 versions of RMS installed on my machine?

Yes. You can have at the same time more than one version
of RMS installed on one machine. For example, you can have
RMS for AutoCAD R12 Windows and RMS for AutoCAD R12 Windows.
Or any other combination.

Note that different versions must be installed into different
directories. However, the different versions can share the
same license on the same machine. For example, if you are
using a hardware lock, the hardware lock will work for all
versions of RMS installed on your machine.