Norfolk may very well be an option, there are several credentialers there right now - however they don't usually send many to Norfolk because like most of the shore clinics it is not really set up to mentor the inexperienced dentist straight out of school that well (unless you are enrolled in the AEGD of course). Same would go for Mayport/Kings Bay etc.
The availabilities change rapidly as orders are written and slots are taken, slots open up, etc, so what his classmate was told several weeks ago may have been accurate at that time and may still be. I would imagine Okinawa orders would be for three years because it costs quite a bit to move you there, and I personally haven't heard of any credentialers going out there (I do know a few officers are slotted for Okinawa following the completion of their PGY-1 programs).
I'm guessing you guys are east of the Mississippi based on what was offered - best bets are that you end up at Great Lakes or Parris Island, either of which should be a good experience and get you up to full speed.
There are many, many more clinics CONUS than the ones listed thus far - but there is a very low likelihood that someone straight out of school will be sent to one of them.