Typically the CO monitor on an air compressor monitors the filtered air between the outlet of the compressor and the banks. It is possible to monitor the incoming air, but isn't usually done, because the compressor runs at a slight vacuum, so there is no driving force to push the air through the analyzer.
It is not likely that your air is medical grade because medical is tested after placing it in the cylinder, each batch fill has a sample analyzed, and then the entire batch is certified. It is way more likely that you analyze your air 2-4 times per year to prove that the process is correct. The standard for such a test is CGA Grade E.
But, as you allude, your air is tested and you have a CO monitor. Nice work.