Will Robinson install the AC system during overhaul at the factory?
I don't see why they wouldn't. My suspicion is that it would still be only for R44 Raven II helicopters s/n 10606 and higher as these aircraft have the wiring harnesses installed to accomodate AC install.
Be aware that if you bring your aircraft to the factory for service, they require that all service letters, service bulletins and AD's are complied with prior to release. This could add to the cost if you were not expecting it.