Hi Marcus,
This pattern is consistent with another one sold in some auction a few years ago. Only the length in such one is shorter.
The text in the offer mentioned a 'quadrangular cascabel' and not a 'cut off tiller'.
So at facing both examples, we don't have as a fact that, this is short tiller was meant to be like that from the beginning.
... or was there a generalized habit to cut them off for some modified purpose
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