This morning, my Model M SSK arrived in the mail. It was shipped from mainland China in about 9 layers of bubble wrap, so I'm sure it arrived in the condition in which it was sent. It was definitely cleaned prior to shipment, and it was close to being new, from a visual inspection.
The SSK turned out to be very much a silent keyboard, although, after a simple check of lifting up a key, it was definitely a buckling spring version of the Model M. It has a nice, cushioned feel, and the tactility is sharp and noticeable. The soft sound, though, is disturbing me after six months of Model F usage. Maybe I'm going deaf from the F noise?
Or is it possible that this one is so well worn that it doesn't make much sound any more? Could we do a remote diagnosis on this condition?