To expand on what Andrew said, no you should not need to recalibrate. If your profile is loaded, then Photoshop will use it.
If you select color settings and click on the pull down for RGB working space, there should be an entry for "Monitor RGB". Photoshop will put the name of your currently loaded profile next to that. If you see something other than the name of your currently loaded profile (or what you think is your currently loaded profile) then you need to address that problem first (and just for clarification, do not select monitor RGB as your working space).
Cheers, Joe