I bought three of them from both suppliers, yes they are different, but I was able to alter it without too much difficulty. Just had to grind a bit off part of the return spring spline, enough to gain a bit of end float with the outer cover on and a gasket. The outer covers on those early gearbox's are expensive to repair, the bore for the kickstart bush, the pivot for the clutch lever and the bore of the clutch plunger all suffer from lots of use.