Colm is extremely well-connected in recreational mathematical circles. He's on the board of the G4G committee, and is an active mathematician and populariser of mathematics. It was he who first broke the news of Richard Guy's passing.
Anything he says is reliable, but by all means wait for other confirmation.
WRT wikipedia, I have a story about the Richard Guy page, but that's not a story for here. Another time.
HN now gets about 5 million visitors a month. In case it needs to be said for some of those folks, the OP -- ColinWright -- is also rather well connected from what I gather and part of that circle (of recreational mathematics, etc).
So I imagine the mods granted the black bar in part on the strength of who posted it. They don't do so lightly and have been known to put a hold on threads in the past to wait for confirmation. They haven't chosen to do so this time and there is likely a compelling reason for that.
