Yes! Exactly! Raise the idle about 4 or 500 rpm and lock the throttle. Pull a plug wire and see what happens. If it is running on only one cylinder, if you happen to pull the wire to the running one, the engine will stop immediately. If you pull the wire to the dead cylinder, there will be absolutely no change.
And, while this isn't the best way to do a "cylinder contribution" test, it could also tell you something about an engine that has BOTH cylinders firing. If you pull the wire to the top cylinder, for example, and take note how the engine sounds and how much the rpms drop off.....the sound and rpm drop should be pretty much equal when you pull the wire to the bottom cylinder and leave the top connected.
The effect won't be identical but there should be no large discernible discrepancy between the two. If there is a noticeable difference in run quality of one to the other, then the lesser cylinder may not be contributing as well as it should for some reason. This might be due to a worn spark plug, a valve adjustment problem or some other mechanical issue and should ultimately be investigated.
But, for now, we are just interested in knowing if both cylinders are firing.
Good luck.
PS...This chore is easier to do if you first disconnect each spark plug boot with the engine off and smear a small amount of DIELECTRIC (tune up) grease on the inside of the boot. Sometimes spark plug boots will stick hard to the plug enamel and make it difficult to pull them off.
Also, make sure you protect yourself from getting shocked from a leaking wire or boot by using a DRY rag or even an insulated pair of pliers to handle the spark plug boot. There are specialty pliers for doing this sold at most auto parts stores but a pair of regular needle nose held in a DRY shop towel or rag will work ok as long as you take care not to damage the wire or boot by pulling too hard with the hard jaws. The "pregrease" technique listed above will aid in doing this without damage.
Good luck.