State Scales

If you are required to stop, there will be a sign before the scales telling you so. The sign will be very specific, so there should be no confusion.
Usually, the scales don't want RVs or non-commercial vehicles stopping, but there are ALWAYS exceptions.
If the sign says "ALL VEHICLES OVER 10,000 GVW MUST STOP", and your GVW is 12,000 lbs., it would probably be a good idea to pull in.

Private vehicles are never required to stop at DOT scales.