They worn parts in my shifter weren't washers, they were shouldered plastic bushings that were a very tight fit. I highly doubt that you're going to find anything at any hardware store that will work.

Here is the factory parts diagram showing the parts that were worn out on mine.



The bushings fit very tightly between the pivot bolt (24597N in the diagram) and the horizontal tube that the shifter pivots on. The sleeve in between the bushings (24061) and the shoulders on the bushings themselves prevent any lateral movement of the shifter on the shaft, finding an off the shelf part that fits in every dimension is highly unlikely.