The 2101s and the 3211s use the same choke cover.
One issue (will not effect the OP as he has the original spring) is that a FEW of the more than 500 different Carter chokes have a spring which uncoils in the opposite direction. If one just buys a cover / spring, best to check the direction of travel of the spring. Your spouse's hair dryer can be used for testing on your bench.
Jon