It really depends, because of this verse in Acts 22:3..."was zealous toward God, as ye all are this day."
Those who are quick to say theirs is idol, theirs is not the same God, if it were the same God, then why would they believe that God => x, y, z..., are adhering to fundamentalist narrow minded ideals. They have never truly done evangelical works that matters. Their work is I preach the word by proclamation and my job is done per the Bible. They did not realize that the great commission has a lesson for us Christians, it is not just a work-base duty, it is that of grace, of love, of learning the creation of God, and these fundamentalists fail significantly in these areas and their pride covered them, their self-desire, self-vindication match that of the Pharisees in Jesus' time.
There is an appeal to the recognition of God that's built into everyone, even the very wicked ones. You may worship God, but you got your knowledge of God wrong. But to deny a connection of those to the true God, well that's just denying them sensus divinitatis and yet expecting them to not deny their sensus divinitatis.