See attached photos. The manufacturing date of the harness will be on the tag. If the date is 1996 or newer, the harness is not original. The new replacement harnesses made from at least 1998-up (possibly earlier) have improved insulation and do not fail after a few years like the originals did.
F.D. = manufacture date (this is the important date)
Z.D. = original design/release date (not sure which)
NOTE: Attached photos show the UPPER engine wiring harness tag location. The tag is similar for the lower harness (to the starter / alternator) but attached near the 3-pin connector bolted to the rear of the CAN box.