Care of Rich Johnston, for what it's worth:
http://www.bleedingcool.com/2011/11/27/where-in-the-world-is-coast-city/Some things occur to me as possibilities:
1) This was a simple mistake.
2)
If it's a retcon, it's a mildly largish one.
3) If Hal Jordan's
really expected to have his USAF uniform traded in via retcon for any other nation's standard issue, some brains are gonna
explode.
4) Californian comics fans should complain about losing both Coast AND Star Cities
if this is editorially expected to stick as a retcon.
I lean more towards thought # 1 here, though. This will likely be fixed for the trade paperback.