If they are listed in a query to [CIFilter filterNamesInCategory:kCICategoryBuiltIn]
, those CIFilters are safe to use. That's a publicly-available query, and shouldn't return any private Core Image filters.
This sounds like a case where the documentation hasn't quite caught up to what they've added, which I've seen with a couple of iOS updates. I might suggest filing a documentation bug to request that this be brought in line. I've done that before and they did update the documentation to match.