Without any sort of official sanction at either the state or the national level then did it really exist? A group of free blacks may have organized themselves and called themselves a regiment, but the state refused their service and do did Richmond. That sounds more like wishful thinking than an actual army unit.
Tree .... forest .... sound ..... the old epistemological razzle-dazzle. Did the James Gang exist? The New Orleans Greys, who fought and died at the Alamo?
Short answer, yes.
Where did you get the information that they were not santioned?
BTW, you argue like a liberal.
Somewhere among my thousands of old newspaper articles is one where the Louisiana governor accepted the service of the Native Guards, which were intended to be home guards. It would take me a while to find it. A quick search of the web turned up this link which said the New Orleans mayor and the governor accepted them. See Link. Page 21 of the link mentions their acceptance by the mayor and governor. That page also says some 3,000 free blacks ultimately joined the Confederate Native Guards.
There was also a company of the First Louisiana Zouaves that was composed of French and Creoles (free mixed race) that fought in Virginia and may be responsible for some Federal reports of black Confederate soldiers.