I have a 1991 (Date Code N) Weber Kettle that was left in the house when I purchased it. The grill is in good condition but I would like to replace the cooking grate, charcoal grate, and the vent at in the bottom. Any suggestions as to where I can find parts? The base is about 22 inches, grill grate 21 inches, and charcoal grate 17". I know I can probably buy a new one for what these parts would cost but I would prefer to restore it.