It's one of the issue sights, if it looks like this:
There were two versions of this No.96 sight, the pointed front "A" & the blunted front "B".
The pointed front was standard for the barrel-mounted position, like on the single-shot Model 68.
The blunt front was used on the rear receiver bridge of Model 69's (not 69A's), so the sight would clear the ejection port.
Whether it was original issue for the rifle you're considering is another matter entirely.
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