Trucks or Buses Left Lane Only. Does that mean me?

You certainly wanted to stay where you were if you were approaching your exit. If that had not been the case then you should plan to move left (or whatever the instructions). In addition to the reasons listed above you can also run into narrow lanes with no shoulder and having 2 big rigs side by side in this area is quite dangerous. You want to be where the most room is available and where your size will not conflict the the road size restrictions.
Be safe out there!