The change in color was probably due to environmental concerns. The lighter color yellow is characteristic of paint with a high chromium content. The hex chrome greatly extends the paint and metal life. Most heavy equipment manufacturers stopped using or reduced the amount of chromium content in their paint in the '80s and '90s.
They build Case backhoes here in Burlington and they went through a huge enviromental cleanup in the late '80s to address high chromium levels in the ground water. Case backhoes manufactured after the cleanup are much more "orange" than they were before because of the absence of chromium.
Based on the color of the second one, I'd say it is much older than 2003 and is not the same one shown in the original picture.