Normal, Up until, I think the 1990's. US mint marks were put in the die by hand. Yes a hammer and a letter punch. You can find high and low in almost every year, Here is a 1953 D high and low mint mark

I look for the odd ball one, like this one. The D is more under the 5

They have been found upside down and side ways. They are all over the place.
Here are 1956 and 1957 ones

It is, what it is, or is it.