easy way to tell.. a camera would need to be wired back to something (internet, computer, dvr unit etc) and a glass break sensor can be completely stand alone. (battery powered no cables coming from the unit, or 1 power cable)
also, you could bring a scrap peice of glass into one of the rooms, break it inside of a garbage can with a hammer and see if the sensor goes off.
if not, call the company and ***** that your sensors dont work cause you real world tested it
(i did this with my viper car alarm glass sensor, smashed a bottle in a garbage can inside my car, and it went off)