Most cal labs would only get a meter in that is rack mounted, though you will find that avionics and military service units send all meters in for calibration, from hand held volt sticks ( yes, even a neon light voltstick will be verified that it is within the specified limits) up to a multimillion avionics test bench ( I drove the van it was in for a month, just to get the 40 year old Citroen van over the 1000km mark while the insides were away for the calibration cycle, otherwise the van did 1km per year) used to do full aircraft ground testing.
The value of calibration is that you can be sure the reading you took last year is the same as the reading you took this year, or that the error is known in both magnitude and polarity. The meter is often the cheapest part of the whole system, the value being in the history.