I can't be sure, no, but I can't think of a single reason why they would lie about something so banal as whether the displayed "originals" are really that. In any case, they do provide their sources.
For example, if you go to the Wikipedia page on the Taj Mahal, they plainly explain that the tombs that tourists see daily, of the Mughal emperor and his wife, aren't the real tombs. Those are down in the basement, below the fake ones.
I can't be sure, no, but I can't think of a single reason why they would lie about something so banal as whether the displayed "originals" are really that. In any case, they do provide their sources.
For example, if you go to the Wikipedia page on the Taj Mahal, they plainly explain that the tombs that tourists see daily, of the Mughal emperor and his wife, aren't the real tombs. Those are down in the basement, below the fake ones.