Question about be quiet! Pure Base 500

Yes, two fans are installed. 👍

Yes, they are, and the description literally says so:

"Two pre-installed Pure Wings 2 fans with airflow-optimised fan blades promise perfect airflow and solid cooling performance. Despite the compact design, the two 140mm fans ensure quiet operation. Up to three additional 140mm fans can be installed as an option."

No, no fans involved.