I have spoken to contacts in various countries and all have confirmed that ship times for Apple's iPhone 5s have been pushed to October.
It seems Gold was the most limited color and Korean parts suppliers confirm that Apple has ordered a production increase for it. It is too early to determine why shipping times are being pushed:
- It could be that demand was extremely high
- It could be that the initial inventory of the 5s was very small due to production challenges related to the fingerprint sensor
It looks like the iPhone 5c is still available in all colors immediately.
Apple likely won't break down sales numbers by device so we won't know how well the iPhone 5c sold but it is safe to say the 5s was the main attraction.