In other words, "no, I have no way of substantiating that but my own sense of 'common knowledge.'"
No one would dispute he will be working with the O-line, but there's (somewhat obviously) a difference between working with the O-line like Bill Callahan would have (having both titles) and working with the O-line like any other OC works with his O-line. That he has that history, sure... no one would argue it makes sense. That he has that history, but it's not yet been said whether he's doubling up... that, for now, suggests it's at minimum an open question, and possibly they've purposely not given him that title.
You're a fan. You're allowed to speculate. You're even allowed to make rash conclusions. But I'd propose there ought to be a little bit of journalist in each one of us that says, "Show me" before being inclined to accept full-throttle any conclusion that has no reliable source's name attached to it. Maybe that's just me.