Usually not. Nowadays, in order to save costs, many publishing houses have poor printing quality. If what you see is different from that in the bookstore, there are two possibilities: First, the version is different from the printing era. Generally speaking, domestic publishing houses print the same book more times, and printing and paper use are not as common as the first printing. This situation also exists in big companies such as Zhonghua Book Company, Shanghai Ancient Books and People's Literature. Some books have been printed more than ten times, and the ink color is uneven and light, and there may be double images; Second, you bought a special book for the internet, which was printed by the publishing house and sold online. The paper printing of this book is worse than Xinhua Bookstore, but the content is the same. Not pirated books, pirated books are illegally printed. I have never encountered this situation, but some book lovers have. Because online discounts are strong, it is also possible to save costs.
You can compare your books with those of Xinhua Bookstore. If there is no difference, it is probably the second possibility.
Dangdang, Amazon, JD.COM, I have bought 10,000 yuan of books, so far I haven't encountered pirated books.