Well, there is actually a very minute difference in the response curve for the '84 and '85, the difference being the 1200 vs the 1300 but prarie hammer is correct, they are interchangeable with virtually no noticeable difference. Thanks for refreshing my memory about the '83 number, it's been a few years, like since '09 since I messed with that stuff! The '90 up is single contact ignition so it's a different animal.
You should find the 10's were the 1200 and the 11's were the 1300...