Even sooner than that. I bought a dedicated server on auction and it was ready 2h after the payment.
Hetzner is oversold. It's not appropriate for production in the same sense that EC2 obviously is. It's fine for staging though.
Out of curiosity, how is a dedicated server oversold?
I'm not familiar with Hetzner personally, but maybe they mean the uplink? I've found that with some smaller providers, advertising 10Gbit, but you rarely get close to that speed in reality.