cmd-S will always save it as 2004, as this keyboard command is the same as
File>Save.

To save a .fla file in Flash MX 2004 that can be opened in Flash MX 2003 I have to "Save As..". The question is: once I have saved such a file, when I re-open it in MX 2004 ( or if I open a MX 2003 file in MX 2004 ) and save it with cmd-S - will this create a MX 2004 file or will I still have an MX2003 file?
I ask just because the cmd-S routine is much faster than "Save As..."