Yes it has in the past. They have also always done international press releases first/only in the past, and then released internationally a month later. One of the reasons why the US got the s3 last was due to the LTE mess, and having to use a different CPU with it onboard.
This time they are doing the press event in new york and then afterwords internationally. This time they have LTE built in for exynos. They want apples market share, but they know their marketing cant compete with apples branding, so wait until the 5s is announced?
Im just saying, a very good amount of rumors that were released about the s4 have been true, and with the change up of press releases and LTE now onboard, they very well could release US first or even possibly a worldwide launch, but thats doubtful.
We will see what they say next week!
USA LTE is still a mess, with all the different Bands that our LTE Markets run on still