Question

[Nevadaref]

Yes. This goes for both sets of rules used in the United States.

Under FIFA/USSF Laws of the Game, the duties of the assistant referees are listed in Law 6. They are under the following caption: "Two assistant referees are appointed whose duties, subject to the decision of the referee, are to indicate:"
In short, the assistants indicate and the referee decides.

For NFHS rules (US high school games) 5-3-2h reads: "...The head referee shall confirm or overrule the assistant referees' signals.
Again, the assistant signals and the referee has the power to confirm or overrule.
In addition, 5-3-2a says: "...The head referee shall determine whether a goal shall count if the officials disagree"