There are two paragraphs from recent updates that show nothing that guarantees shipping in December 2016(emphasis added to the below quotes is mine).
From October update:[quote=“dan, post:1, topic:3179”]
Q: So does this mean you’re absolutely certain you’ll ship on schedule?
A: No. Unfortunately our schedule can never be absolutely certain, because production surprises with far-reaching consequences can arrive at the last minute. We’re working every waking hour to get your Glowforge on time, but if you’ll forgive me repeating myself, meeting our schedule is the second-most important goal we have as a company - eclipsed only by making sure your Glowforge is as good as it can possibly be.
[/quote]
From November press:
Planning does not equal delivering. I planned on making a lot of art in December, but that sure isn’t happening because we’re moving /shrug