In the age of mass manufacturing, you can go buy two (of the same) knives and have them be so close that there is no way even a forensic team would be able to tell the difference from the wound inflicted. Never you mind that angle of attack, defensive response, situation, etc. would all change the knife wounds in more ways than that.
There are other, more meaningful ways to narrow it down to a single suspect than that.
In the age of mass manufacturing, you can go buy two (of the same) knives and have them be so close that there is no way even a forensic team would be able to tell the difference from the wound inflicted. Never you mind that angle of attack, defensive response, situation, etc. would all change the knife wounds in more ways than that.
There are other, more meaningful ways to narrow it down to a single suspect than that.