They wouldn't be there. Since Broken Steel added them. The only "legacy content" in New Vegas is what was in Vanilla Fallout 3.
There is a Hellfire armor mod for NV in the nexus. I say just download that and give it to Enclave soldiers.
Edit: I'm kinda surprised the Ghouls won, not that I love the BoS that much (close though) but I used Enclave Commander to take AAFB and those BoS paladins cleared the base out w/out much help from me. (I ran out of any healing items, so I ran and hid)