Could be the letter designator at the end of the part number is a revision referenceI'm not sure either, but I was hoping to see some revised part numbers. In most of the Fische's I've looked through in the past they list the original part number but will not let you select it, then they list the superceeded part number, which you can order. Seems Tesla just list the current part number, so there's no real way to tell if it was updated or not.
i.e. A, B ,C etc..