[Transmission]

Isn’t there like a VT clock before the programme starts, that might have the recorded tx date on it?

Yes, but you would have to specifically go back to check the clock or slate, it's not something you'd see just before it goes to air as it plays from the first frame of the programme. That kind of check is something that BBC playout routinely does, for example, but I'd expect it's not standard practice in a news gallery where they're playing reports and clips far more often than programmes.