There was a difference in the decal font between the Mk I and Mk II Enigmas, but I don't know about the Mk III. The Mk. I was finer, less blocky script. I'd check 'Completed Listings' / 'Worldwide' on eBay and Google Images to find comparisons.
I have 2 Enigma MK111 10ft 8wt 3 piece rods.
They are a copper colour with black reel seat.
I believe the earlier ones were 2 piece.
Jonathan Jones my friend designed the Enigma Mk1 Seatrout Special for Airflo with his name inscribed on the blank.There is one on ebay for a lot of money.
Mk111 is better than the Mk11 according to JJ.
I have landed salmon up to 17 pound off the Coquet,and a few off the Usk on them and are superb rods.
I could ask him if he can remember the exact differences .