I'm in a similar position, but I can tell you that it's not a FedEx ID. Macfly77 might be correct however previous shipments from Telltale via USPS have not had an ID. I had already started talking to Amy (Support) before I spotted this thread, so perhaps she will shed some light on it.
One final note is that I do agree with Macfly77 that there is no reason to think they haven't shipped and I suspect it's just an error with shipping details (as I understand they have been very busy) and it's in transit as we speak
