A step 1 of 239 is high enough where it won't cause you any problems getting interviews at top programs, but remember it is not the only factor. Many students feel that this score is what defines their application, which I think can be a mistake. You need to score well in your core clerkships in third year, especially surgery, internal medicine ( and ortho if you are taking it). If you look at some of the "objective" screening tools that have been released by program directors (the references to these papers are in previous threads) many times third year grades are the most heavily weighted factor, just something to think about.
As far as getting exterships, you should have no problem at all, most programs do not have an extensive screening process to do away rotations. In your case even if they did, you should be able to "pass" it.
