I can’t find any other photos. It would be nice to see the back side of it. How would the altar hold the wood for the sacrifice without two more horns on the back? Do you know of any other links that expound on this find?
The sacrifices may have inovolved the burning of some kind of aromatic plants etc. Overall, I fail to see what the problem is. The four-horned altars are also called Shiloh altars, but there are plenty of examples of two-horned altars, an image search will turn them up.