Area 51 CAD Files in Metric?

Hi there I'm new to the forum, haven't built a machine yet I've just been playing with AutoCAD and trying to change around the AREA 51 cnc plans.

I've extensively searched the help section of Autocad but haven't found my answer.

Are the AREA 51 plans only in Imperial Measurements and if so can I change them?

Cheers,

Marsh