I am pretty sure that is quite okay.  
Crop Insurance covers the crop that was insured.  Once that crop is done, another crop can be planted.

Last year, we had a lot of corn fields harvested early for silage.  Some guys came back and planted an oats crop for fall forage.  I am certain at least some of those corn fields were covered under crop insurance. 

The only criteria would be that the crop insurance adjuster needs to verify the loss before the insured crop is harvested or destroyed.  In case of harvesting corn as silage, if the adjuster can't be there before harvesting, then rows of corn need to be left standing until the adjuster can make the final assessment.  This must be done under the guidance of the crop insurance adjuster - this is not the farmer's discretion to let rows stand and harvest the rest.   This point was clearly stated at a recent winter crop insurance meeting.