I guess in 1961
they must have used some and then made it official in 1962
- the article you reference describes both as the first year. Certainly the axles on my 1963
are bolted on, thankfully. Interestingly, they still have a negative angle, and may still have some life in them. I still intend to replace while access is easy. At the moment I have the axles nicely exposed with the floor up and bellypan off. I've been soaking the bolts to loosen them, and it looks like they'll move easily.
I believe my Sovereign
spent much of its life sitting in the same place in Quebec. There is very little evidence of years spent rolling down the road, although while gutting the interior I did find some postcards from mid-60s locations on the Montreal-Florida route.
Sadly, I also think at some point a large amount of ice slid onto the roof from an adjacent barn. I've got things mostly back into acceptable shape, and the pieces are starting to go back together now.