Depending on the season and temp outside I have found for my chargriller super pro I don't need them for the winter. For the summer I took out the thing that holds the hot charcoal and flipped it upside down and that worked fine. I'm lucky like most of the guys that mod'ed and have someone who is a sheet metal mechanic. I had 3 tuning plates made but only use one right by the outlet for the heat. Like posted before you can use some foil and be good to go. I really think that a lot of those mods are from very bored perfectionists
But your grill can be a great smoker with just a few small adjustments. Get a better temp gauge, get some exhaust tubing for a dryer attach it to your exhaust pipe inside the grill down to the grate and if needed use the charcoal pan as a baffle plate.