Yes... you can check it that way... but if you have 2 carbs... you have to disconnect them from each other, and test them one at a time.
There are 2 problems you may run into . If the needles are dry... you won't get a clean "Pop." And... you may only get one pop if you try to check it a second time.
It really is best to remove the carbs and do it the proper way.
The only thing I do with the carbs on the engine, is to check the needle and seat to make sure they hold pressure.