The length of the bytes are okay.
If you look:
\xB8\x02\x00\x00\x00\x41\x87\x84\x24\x50\x01\x00\x00

will be replaced with
\xB8\x03\x00\x00\x00\x41\x87\x84\x24\x50\x01\x00\x00

The byte lenght is the same, but you are changing x02 to x03.

But the value which has been changed, is the false one because it modies something in the code which applies to an Gui.xml procedure and not to the license mode information.

you can find the XML files in each plugin folder inside /Library/Arturia/.
For example for "Acid V" the file "Acid V.gui.xml" is located in "/Library/Arturia/Acid V/resources".