Been thinking about this again (another sleepness night).
The die used in the machine to stamp this out can't have been broken otherwise more material, not less, would be left. If it was broken and then repaired (die heads aren't cheap to make so repairing it makes sense, toolmakers are skilled craftsmen) then there would be more material in the tuner head. I'm going with a different die was made and perhaps they were looking to align this with something else.
I will now do my best not to think about this as I walk the dog.
Rob