Doesn't affect gameplay at all, but the front sight and flash hider (on the model, not the attachment) on the Mk14 are inaccurate for that model of rifle. Currently it has a standard USGI combined flash hider and front sight unit, but the Mk14 program rifles have some combination of SEI gas lock mounted front sight (trident/fork or hooded) and either a Vortex or Surefire flash hider (depending on Mod 0 or 1 or in between).

Reference photos:

• Front sight components (item 2012 or 2013 & 2018)
• Vortex flash hider (item 2000-V-A2)
• Surefire flash hider (since discontinued and hard to find reference photos of)