The accuracy standard you specified is .00003937" , or 1 micron. Plotters are not nearly that accurate, they use stepper motors and are open loop (they have no position feedback), I would doubt they are .01" accurate.
To measure to a micron on a positioning system you would use a high precision linear scale. You would also have to have an environmentally controlled room, and the system would have to be on a concrete pad that went to bedrock. If you breathe on a micron positioning system you can cause positioning error.