To answer your question it is very possible it could happen but yet very unlikely. Statically, with no hydraulic power applied, WOFW through whatever means and pull the gear handle to the retract position will have no effect. Now apply hydraulic power in the above scenario, depending on size/weight of the aircraft the main gear's will not tract but your nose will in most cases.
This is pure speculation of course but it can be easily tested even within the confines of most maintenance manuals. GEAR PINS INSTALLED, hydraulic power applied, lifting the gear handle will test all hydraulic carriers on the retract side for leaks and handle down all hydraulics on the extension side. Now in either scenario go out while your testing this and move the gear pins back and forth but do not remove them. You will find probably your able not to move the nose gear pin but the main gear pins you probably can.
I remember in the Air Force these fighter pilots would lift the gear handle just before rotation. So when the aircraft rotated, they would pull immediately into a vertical climb. I watched this on occasions and sure enough the nose gear would retract but mains stayed down.
The most important factor to this, is weight of course, the more weight and resistance acting against the retract actuator, the less likely it will happen.