I always try to find LUA files personally. If you really wanted you can convert the LUA into LUB giving it more security.
Seems like you catch on pretty fast. Yes, you need matching LUA/LUB for your client. Also make sure your client diff reads "LUA before LUB" or vice versa.
P.S. If you change your LUA/LUB It will mess with your customs, you will be reimporting them again.