I wouldn't worry either way, its not a firearm.... but the beauty of Nikons is they can be carried in Condition One safely, just thumb the wind lever open and fire away.
Being a toolmaker I understand intimately the nature of metals. A spring under tension after a while will lose some of its strength. I would leave a camera in storage not cocked.However leaving a camera shutter cocked for a month or 6 probably wouldn't hurt it provided its stored correctly.
Even so, I feel that you should exercise the shutter of unused cameras once a month, this gives you the excuse to play with your cameras.Unlike firearms dry firing a camera without film/ammo won't hurt it.