RTW is intended to generate ISO/ANSI C code, and as a result of that, it doesn't generate any special commands in the code for targeting multiple cores. It doesn't prevent you from doing this in any way, but it also doesn't generate anything extra for multiple cores either. There are a variety of techniques, such as S-functions, Custom Storage classes, and customizing your own "main" that would allow you to add extra code that may help do this.
Along similar lines, as long as you have an ISO/ANSI-compliant compiler, you should be able to use the generated code on any processor you like.
