I was able to do some research and according to the manufacturer's specifications, it is indeed the fanless, dust-protected and robust housing as shown in the photos.

Yes, the RAM (DDR5 RAM) and mass storage (M.2 PCIe) for the product "NUC 13 Rugged (Intel Atom)" from ASUS must be ordered separately. The device is supplied as a barebone, which means that it does not contain any pre-installed RAM or mass storage. It has SO-DIMM slots for up to 16 GB DDR5 RAM and an M.2 slot for PCIe x2 NVMe SSD, but these components must be purchased and installed separately.