Optically speaking, irons zeroed by one person should be zeroed for everyone. The reason people say zero is unique to each individual is if the zero compensates for consistently moving the gun up/down/left/right when you pull the trigger. For example, on a pistol if your trigger control is bad and you keep pulling left, then shifting the sights rightward will make you 'zeroed' but that's addressing one problem with another.
Take note, if you ever put a red dot on there, the zero WILL shift between a person wearing contacts, another wearing glasses, and another having good eyesight. Reason is that glasses, depending on thickness and material, bend different colored light differently (called chromatic aberration), and red is one of the "most bent" colors just like in a prism. This is not commonly known but something to consider.