Great post Blue. I'd reckon that method for identifying genuine Autos is just about fool proof. At 128,000 even I'm surprised they've gone that high. Just can't argue with that kind of evidence.
And Gizmo, I'd say you 100% have an Auto there. The wear on the those axle housings is just about as clear as you could hope to find. I reckon it must have run a good few years with the setup attached to achieve that kind of wear, not to mention the breakages. What engine number has it got now?
This is up on ebay and is a fantastic serial number record. whilst it doesn't tell us what type of mower the guarantee was for, it does give a very nice month/serial number correlation. It's quite faded, but reads: