1982 Idle control unit part number verification

Does anybody know the correct part number or numbers of the Idle control unit for the 1982 528e? I had pulled one off of a 1985 in the junkyard...It reads...1 286 133.9. I saw one on ebay that read ...1 286 133. I know that certain electronic parts were upgraded and may not work on the 1982, but am just checking before I pitch it...