Translation:The books are completely new and have not been read yet.
Why does the past tense seem out of place to you? It refers to something that occurred (or didn't occur) in the past, and we don't have the perfect tenses in Hebrew.
Yes, it was just the particular translation I was seeing. When I saw another English translation of the same Hebrew sentence later in the lesson, it made perfect sense to me.
This course needs to brush-up on idiomatic and common expressions. "Brand-new" is a completely valid English translation.