There may be a subtle difference but I don't know what it is. I have two '62 Plymouths and my convertible has a '63 harness in it. If you use a '63 harness in a '62 it would be wise to check the wires at the bulkhead connector to make sure the arrangement is the same. But, as far as I remember it was a plug in swap. The factory part numbers are different but it could be something as minor as the length of a wire or two. The difference is not in the instrument panel plug as the dash clusters are interchangeable. According to the parts book it doesn't make any difference whether it's a Savoy or a Sport Fury, they all use the same harness. If you're looking for a harness try here:
http://www.ebay.com/itm/ws/eBayISAPI.dll...vectorid=229466