Picture yes!
Or at least the make and model motherboard.
Do you have the motherboard specifications and accompanying diagram. How are the "other 4" SATA ports labeled?
Could be non-functional placeholder SATA ports for future use. Removing the "weird cover(s) may not even be viable.
Not at all uncommon for manufacturer's to use the same design but then blanking out connection ports, reducing component costs in order to offer less expensive versions.