After compiling, there used to be separate uncompiled and compiled structure files. Things have changed in 4D 2003.
In 4D 2003, after compiling, you no longer have separate uncompiled and compiled structure files, This is because 4D 2003 stores both the interpreted and compiled code in a single structure file, allowing you to rapidly switch between running in interpreted mode and compiled mode while developing your application.
After compiling, if you select Run Compiled from the Use menu, the uncompiled structure icon will change to the compiled structure icon (the next time the window containing the structure file updates).
And, if you are running in compiled mode and select Run Interpreted from the Use menu, the compiled structure icon, will change to the uncompiled structure icon (the next time the window containing the structure file updates).
You can create a separate compiled structure that contains only the compiled code by compiling your application and then selecting Build Application from the File menu.