Hello Seth500. I am not sure that it will solve your problem or not, but that is a good method to do.
Ther's the last free version of IcoFX, download and install it.
IcoFX.zip . it will do a nice ready reference . Click on tools > Resource Editor
The resource editor window will appear. Click on the open button
in the open resource dialog, browse to imageres.dll and open it
.... and all the icons are there, with perfect numbering .
Now, For reverting things back to default, the best way is to save copies of the original files before the modification is done. When needed, just replace those.