There were two mistakes in the above. For the format you need to make the output of that special date/time, and the parameters to time.Unix
are the other way round (playground)
const createdFormat = "2006-01-02 15:04:05" //"Jan 2, 2006 at 3:04pm (MST)"
fmt.Println(time.Unix(1391878657, 0).Format(createdFormat))