While it should generally work to register the embeded versions, some new formats that are added to LAV may not work properly until you re-register them again, since information needs to be written to the registry.
In general i strongly recommend to use the LAV installer if you want to use LAV in any other tools, since it also does some additional setup. If all you want is custom settings in MC, registering its own copy may work, assuming you re-do it occasionally after an update.
In short, only do it when you really know what you're doing. If you don't know how to do it, you probably shouldn't.