When a device is labeled “Contains” FCC ID XXX-XXXX, typically, this means the wireless component of the device has been tested to follow FCC ID certification. In many cases, this implies the entire device is not FCC certified and the manufacturer/distributor is claiming the enclosure modifies the performance of the chip in a negligible way. The rules on getting a device FCC certified vs just using a certified chip depend on the wireless frequency, power, and enclosure.
Be sure to read all FCC regulations or consult an FCC expert before simply putting a “contains FCC ID” label on your device as it may not be legal.