Hi Fernando,
As I said before I am no expert....but the comment about the 'sprue' being of good quality bronze and therefore likely a reproduction seems strange to me.
As Kronckew pointed out these are sometimes classified as chisels... with the 'sprue' as the contact point as the 'chisel' is struck by the hammer / mallet. Surely then, the bronze quality should be consistant from the blade 'edge' to the upper surface of the 'sprue'. Or am I missing something....certainly wouldn't be the first time
Regards David