You don't have to take the sideplate off to do this check. (you shouldn't remove the plate)

You can both feel and hear when the cylinder locks on the cylinder stop, and when the hammer reaches the bevel in the trigger and locks back in SA. if you pull the hammer back very slowly, the cylinder should lock on the cyl stop prior to the hammer reaching the trigger bevel.

You can actually cause damage operating the action under spring tension with the sideplate removed. The mainspring strain screw should be loosened (tension relieved) any time you plan on removing the sideplate.

__________________
Ret. LE, FA Instr, S&W Armorer