The rollmarks, mostly. The MKIV National Match pistols made before '85 or so had the collet bushing. The early National Match pistols had the spur hammer, but the later Series 80 National Match Gold Cups had the oval hammer.
The most notable difference (other than the rollmarks) is the trigger. The older National Match pistols used the slotted trigger, while the new Trophy pistols have a 3-hole trigger.
Thanks for the reply. I ordered the SS Trophy.
I just got a Trophy model couple weeks ago. Much different than some of the Cups I've had in the past. Different trigger, hammer, bushing and has a beaver tail now. Rear sight is marked Champion instead of Eliason. Shoots better than previous ones!

It's the one in the middle!

Here's the one I just bought. I hate the black rubber grips so they went back into the box. Very happy except the target spring was riding against the bottom of the trigger guard and rubbed the finish off. What is the matt finish, blasted or some kind of spray on???

Its bead-blasted stainless. Congrats on your new Colt! The grips look fantastic!