Of course the finger pointing upward is a conventional piece of iconography, trading on the folk notion that Heaven is up above in the sky. Let’s remember that God is held to be perfect, which means he must be omnipresent (for if he were localized in one place, that means that he could change places, and that implies that he either moves toward a better place or away from it). There are no degrees of perfection: one either is or one isn’t. So to think that God has one specific address is theologically dicey.
But the finger pointing upward is shorthand for “we believe our loved one has departed for Heaven,” i.e., 1) that they lived a good life; 2) that they are not gone, despite the void we feel in their absence; 3) that they are not in some sort of pain; and 4) that (assuming we live a good life) we will meet again.
But what about when a stone bearing this iconography topples? Then the finger may be pointing any which way. In this case, the finger is now pointing toward the nearby town of Throop, Pennsylvania, which though a fine place indeed, may not be our, or the deceased’s, idea of Heaven.