Numbers can be confusing. The part numbers and cast numbers on the Upper A-arm do not match. here's an overview:

MY 1978-1985:
Upper A arm Left, part number 928.341.27.33, cast number 928.341.457.22
Upper A arm Right, part number 928.341.28.33, cast number 928.341.458.22
Lower arm, part number 928.341.017.02, cast number 928.341.413.06

MY1986-1995:
Upper A arm Left, part number 928.341.27.37, cast number 928.341.031.31
Upper A arm Left, part number 928.341.28.37, cast number 928.341.032.31
Lower arm, part number 928.341.017.04, cast number 928.341.413.08