You could technically visit a local California smog check station and ask them to perform an emissions test on your sanding machine utilizing their smog check machine; which is in essence is a 5-gas analyzer.
The question is will the EPA approve emission test results from a smog check station which is designed to inspect vehicle emission results as opposed to an emissions lab which is dedicated to performing emission testing specific to Class IV complaint gas engines.
Check with the EPA. If they say any gas analyzer result will do, then visit a local vehicle emissions inspection station and ask them to perform an emission test on your gas engine while their smog machine is in manual 5-gas inspection mode. This that said... a stand-only 4 or 5 gas analyzer (if you can get your hands on one) would probably suffice also.