No, not really. The TiVo service on the DirecTV combo boxes is technically "DirecTV DVR" service and is considered a DirecTV product. If you want to use the TiVo retail hardware with cablecard/OTA then you need to buy the hardware and get the service directly from TiVo.
I still have two active DirecTV combo units with grandfathered lifetime service that I bought almost twelve years ago. I'll be phasing them out over the next few months in favor of the 6 tuner TiVo Roamio with lifetime service I just bought.