Hi imsofaman,
Before I answered your question I wanted to run it by our District Frequency Coordinator, Dan Williams. Dan is eminently qualified to answer your question and a member of the AMA Frequency Committee. Here's his answer,

"Short answer? Nope - he can't tell.
No scanner can definitively tell whether a transmitter is out of calibration for bandwidth. To do that you would need a spectrum analyzer. GOOD scanners can tell if a radio is off frequency, but that's it.
Dan "

Dave