lets see. The simplest way to put this. The 40s through 70s were green stripe machines. Then in '90 came a few distinguishing changes: 1) The start of the large P-3 (a P-3 was always available in the small machines) in the larger machines. 2) The addition of a Hawks head towards the end of the "Green Stripe." 3) The change from the conventional tan cab interior to an "automotive grey" interior. The 91's still had the P-3's in all, the "automotive grey" interior in all, and the change came in the striping. The stripe was changed from Green with a Hawk's head to Orange. Now I will say this. When looking for machines, we visited Cole Implement in Media, Illinois. I remember looking at an R-40 there. I, using the convential wisdom I just presented, asked him what year the machine was. He told me it was a 1990. As the machine had an orange stripe I knew he was incorrect. If it had been a 1990 machine it should have been whatIJIJIJ That's correct, Green with a Hawk's head. I thought I had the dealer. Then he told me that nobody liked the Green stripe. Once the orange stripe came around which everyone liked, the dealership began to paint the formerly Green Stipe machines orange. Hope you find something useful there. Have a good one.