Nope, there isn't. Just speculating.
Really though, if they weren't able to manufacture more than 1m just for the launch, there's bigger issues.
I honestly think that the way they've been cautious about it, 1 million units weren't available for the US market. Probably will be worldwide, but I honestly think that an undersupply is good for marketing and getting those sell out headlines out of there. Can create a demand for those on the fence.