For this type of change one will have to load/enter the module the first time to have it work. So in this case you'll need to load a [saved] game anywhere before landing on Dantooine.
The basic idea is to have the game load the [object] templates before they're spawned into the module, otherwise they still carry the previous data prior to the edited ones.
No you don't, and never have to edit the RIM -- ever, at least in K1.
The game prioritize MOD over RIM, so any change you make to the MOD will take precedence shortly -- that, if you load it right. One will not need to edit RIMs' 'cause they're critical for rollbacks and/or debugging without having to reinstall the game.