Exactly. I'd suggest it's actually highly likely that quite a few of the crew who managed to successfully abandon the ship (together perhaps with some passengers who realised what they were looking at) were able to view the bow of the ship before it sank. And they'd have seen that the bow visor was entirely missing, and that the vehicle ramp had also been torn away from its stowed position.
And if they did see all this from the life boats, it would have been immediately entirely apparent to them exactly why the ship was sinking: the catastrophic failure/loss of the bow visor, coupled with the huge damage to the ramp, had allowed seawater to flood into the vehicle deck. And they'd have known enough about the dangers of serious water ingress to know that a flooding of the vehicle deck would easily be enough to destabilise the ship in terms of list and loss of buoyancy to the point where the ship would inevitably sink.
So yes, I'd say it's eminently possible - probable even - that within even a few hours of the sinking there were plenty of reasonably-credible reports of the primary cause being the loss of the bow visor and the consequent damage to the bow ramp. There need be no requirement whatsoever for any skulduggery or conspiracy-theorising when considering how the "bow visor" causal theory found its way to Bildt's ear so quickly.