After conducting a thorough search, it appears that obtaining a free product key for Nikon Camera Control Pro 2 through official channels is not feasible. The software is a commercial product, and like most commercial software, it requires purchase or a legitimate free trial period.
Camera Control Pro 2 is a paid professional software and does not have a "free verified" product key. It typically costs around for the full digital version. Backcountry Gallery Photography Forums nikon camera control pro 2 product key free verified