Tip: After editing your overworld, make sure to use an EMPTY save file, as save files with progress may load Mario's position based on previous versions of the overworld. Note that altered level flags will also only take effect on new save files.
I think I know what you're talking about. The IDs you are talking about would be labled as a NLST in the ROM Manager. Each NLST would be a different instrument pack used for specific tracks -------------------- IS THAT YOUR FINAL ANSWER?