I believe that's correct. Most of us here are still relearning the particles (for honorifics) while forgetting we need to relearn them in the first place, and thus we fail to even pay attention to them.
~님 is a particle added to addresses to attach additional respect to the address. It is often found at the end of high ranking titles like "teacher" (선생님) or "boss" (사장님). But you can add it to any address you want.