It probably wouldn't hurt to just pull and check. If it's dirty, then clean. Of course...it all depends on the environmental conditions yer vehicle is running in.
I think the newer types of MAF sensors (wire or film) use a heated element. The thermistor reads the amount of temp change from air flowing (cooling) and that is one of the baselines that the computer uses to compute airflow... So I don't believe that you can just take a static meter reading and see if it's working properly...
