The Day the Earth Stood Still (1951) release date?

[BigShadow]

I've seen several references to various release dates for The Day the Earth Stood Still (1951).  The most common are September 18 and September 28.  As far as I know, the September 18 date is the premiere, however the September 28 date is listed as only being released in Los Angeles, CA.  Was this another premiere or limited release, or is the 28th considered the actual "release" date?  Any help is much appreciated.

[Mike Scott]

IMDb says September 18 was the premier in NYC and the Sep. 28 date was the LA premier (I guess).