I initially had a delivery date of 10/3 for a non-SO 3G, ordered within an hour of the website going live. 3 hours later I changed to a non-SO wifi and my date dropped to 10/11, where it remains.
I don't think that Amazon is specifically favoring one device over the other. I think that they may have underestimated the popularity of the non-SO kindles and too few available for shipment on the first day. (Meaning that some people who ordered early would get them, but many people would have to wait.)