Probably not, given that the up9 and s97 will also one shot headshot on lower difficulty. Higher difficulty, you should probably be using the F57. Pistol mastery will also divert points from S.Aim and Dexterity.
Firstly: This wikia isn't actually run by Cishnato. Secondly, just because there isn't an explicit 'no' doesn't mean that it's likely.
Shouting makes nearby guards suspicious, and they will investigate. Aiming down sights is silent.
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