Why Gray City?

While neither Army Men 3D nor Army Men for PC (1998) specifies anything more than the name “Bourbon Street” in the Army Men 3D mission (the penultimate one, just like in Army Men 1998), the growing presence of the Grays and the fact that since we arrived in Bayouland we see that there is a gray vehicle factory, the mansion of Grey Colonel Cajun Joe, among other signs, everything indicates that it is Gray territory. Therefore, the city we arrive to must be Gray, right? But the information confirming this comes to us in this poster from the Army Men 1998 box.