Funny, Im almost unsure if I should try to respond to your question or take the opportunity to express my opinion on unrelated subject-how you use your refer...
I'm unclear though to the features your describing that might be advantageous and worthwhile to swap refers. If I had two campers, one 6 years newer, that would cause me to consider swapping. However the amount of actual work involved I couldn't justify, especially IF the only reason for swapping could be done in either case. Not sure Im making sense but they are both 3-ways? Only difference as I'm understanding is 'how' they are switched between sources?
In your case you want to run 12v on road, and either will? I wouldnt think worthwhile to swap for the ability to set in 'auto'- have plugged in the house to pre-cool, unplug when ready to go, start the truck and it switches to 12 volt (or gas if on) automatically, verses manually selecting AC, going back in to manually set to 12v (or gas).
Just my opinion-only you can decided if its worthwhile for you.
Our, an '01 3-way, has the auto source switch-over ability but I do not use. I manually select the source I want to use (or in actuality select the 2 sources I do NOT want to use).
IF you decided to swap though Id compare the actual specs for each 'virtually' identical modle, specificaly physical dimensions. 1/2" here or there might all mute.