It appears from the photo that the same crescent shaped cut-out is visible on both boots, or am I mistaken? I feel like that may be a deliberate notch that is there to indicate the "center" of the tongue base. When the closing department that stitches all of the leather pieces together is working on closing the upper, they have marks to guide them (which are mostly silver leather marker lines that come off with buffing). I have a pair of Finches, and the center pinking point on the saddle is slightly longer than all of the others, which I believe is for the same purpose. In the end it is personal preference, but if it is not visible when the boots are laced up, I would just keep them.