Nikonrumors.com posted the D600's supposed specs, from a Malaysian forum. If you read the comments, a number of readers have complaints about the sync speed (supposedly 1/200), shutter speed (tops out at 1/4000) and no mention of a commander.
I myself am guessing as well, but I have serious doubts about the sync speed and shutter speed. Historically, all higher-end Nikon models have incorporated all "features" that have been included in older lower-end models. So, for example, the D800 is higher end than the D7000. If you look at the specs, the D800 has all of the D7000's features or improves upon them. See this comparison.
But, you may ask, the D3200 can use the WU-1a wireless adapter whereas the higher-end D800 cannot. Yes, that's true that's why I said higher-end Nikons incorporate features of older lower-end models. The D3200 is newer than the D800 therefore the D800 doesn't necessarily include everything the D3200 has. Similarly, newer lower-end Nikons can sometimes leapfrog some specs of older higher-end Nikons. For example, the D7000 has some specs that are better than those of the higher-end D300S. Also note that I'm talking about 'features.' I don't include resolution or fps or a swivel-out screen. It's kind of arbitrary but I think you know what I mean.
Going back to the D600 specs. The D600 is higher-end than the D7000 and of course the D3200. That's why I believe the D600 will have equal or better specs than the D7000 (and certainly the D3200) in every respect, meaning a sync speed of 1/250 (1/320 with slight reduction in range), 1/8000 shutter speed, and a commander mode. That is also how I speculated that the D600 would have a wireless adapter (like the older and lower-end D3200), which apparently has been all but confirmed by Nikon.
Of course, it's possible that for the first time, a higher-end newer Nikon (the D600) won't have better specs than a lower-end and older Nikon (D7000), but I would not bet on it. So let's not start a riot about the D600 sync speed or shutter speed or commander mode just yet. :)