I ordered mine through Amazon.ca as well.
I don't think it is a "fake" USPS tracking number. I think they printed the shipping label, but the items are not ready to ship yet. (One of mine said available Oct 1 so I am assuming this is the case)
when I search my USPS tracking number is says Pre-Shipment Info Sent to USPS
My understanding is that when you buy Spigen on Amazon, you are buying direct from the manufacturer, can't get more credible than that.
Correct me if I am wrong.
At this present time, Apple Stores in the USA is only selling "contract-free" T-Mobile version, which means, it is still locked to T-Mobile, you are paying the full price, not tied into a contract.
That's the only version you can buy "outright", meaning without being tied into a contract: with the other carriers, Verizon or AT&T to name a few who requires contract, but you will need to contact T-Mobile to deliver the "unlock" via Apple iTunes Whitelist Database.
From what I heard and read about, T-Mobile will not process the unlock until you are with them for atleast 30 days and/or 3 months.
Hope this provides the insight.