Presumably this was an extract beer with a top off of water? If so, it isn't unusual to have a strange OG reading since it is difficult to get the wort mixed. Even if it was something else, all it means in the end is that the beer would be slightly heavier, slightly sweeter and slightly higher in alcohol content. Notice the key word "slightly", enough to tell the difference, but not enough to make a messed up beer. You should be A-OK