I thought the solution was east... swap the cages and lower arms to put the older cage on the older body.. Now I see the upper arm was a little shorter on one to allow clearance. Damn... Wrong again, it what just the way I was holding them next to one another, the arms are the same!

Edit: Looking at the hillary's auction pictures I see the last one (latest one) has allow parts. The more I look at the later model I have the more I think it was meant to have alloy arms, A test fit with alloy arms proved to be harmonious. Why the older brass arms made it onto this one I will never know.