Might work, but not guaranteed (i.e. might stop working any time, even if it does now). For example, there also might be some related info in registry - so copying only the files may get the program into an inconsistent state.
Honestly, there's absolutely no need for backing up the current definitions (if anybody reinstalls the program, which is a rare thing itself, they can simply download the new ones) - so there are no plans to spend time on it.