Why should this not be the manufacturer's number of this product? -> http://www.gskill.com/en/product/f4-4000c18d-16gtzr
Just because this product may not be listed in the QVL list does not mean that this is a mistake here and that it is not compatible.
In principle, you can use all DDR4 Rams on DDR4 mainboards. The maximum OC value of the motherboard is the maximum guaranteed by the manufacturer, which means that it is designed for this value. With given cooling, it is also possible to achieve higher clock speeds, as with the processors.
It is best to watch a few OC videos on youtube and slowly approach the desired value.
Best regards