If we read it correctly.
"Yes, if you have selected an iPhone for use on AT&T, Sprint, or Verizon. When your iPhone arrives, all you have to do is turn it on and follow the onscreen instructions to set it up."
I'm assuming it will be ready with those phone carriers. If you read the second sentence.
"If you have selected an iPhone for T-Mobile, it will come with the appropriate nano-SIM, but you will need to contact T-Mobile or visit an Apple Retail Store to activate your iPhone."
It says that the sim will come with the phone BUT (that's what stood out with me). Why would we need to contact T-Mobile if the phone is not already setup like the other carriers? Maybe because its unlocked and we need to contact T-Mobile to lock it under them? Sure its a contract-free phone, but they could still lock it up with T-Mobile for T-Mobile users to use. Plus the fact we are paying full price for the phone. And, Plus x2, others have seen this the previous models (like "jgz91354" has pointed out).
Now, lets just wait and see when the phone is in the public's hands.