bottom. On the bottom I guess it is the way the picture was taken because the 1 - 5 is plain as day and in the picture about the hyphen looks strange, it is the angle of the picture.
Here is another picture of the 1/2 gallon Ball Mason with markings on bottom. I was not sure if I included this one or not. It is marked 1 - 5 except the 1 is straight like an i without the dot. I am unsure of the exact color, i am unsure of the year, I am unsure if it is an error jar or not...