I have been thinking about this and you could slightly modify the stock setup by using a heavy plate, 1/8 steel, between the housing and the plate that holds the seal. You could make it like the plate that holds the seal but with a slightly smaller ID on the big hole. I have seen this configuration on machines. Another way to straighten this out would be to purchase the c-clip elimination kit that is available. I have a theory as to how this different set-up may have come about. GM was making these rear end assemblies and then they sold the business to American Axle at some point. Maybe it was an easy, substandard, way to get by when they first took over the business. And since the c-clip rear ends soon followed, maybe the c-clips were an improvement over a set-up where the seal took all the side loading. The solid c-clips are much better suited to hold the axle than a seal. It's an engineering nightmare for a production rear end to be made this way. Hopefully, there aren't many out there. If they are a late 69 thing then it may be that it was only a particial run. Think of it as the 'missing link' between the inboard held axles and the outboard held axles.