Page 22 of the maintenance and service guide show (10) the M.2 wlan system board connector, and (2)/(3) as the pci express x1 connector.You are confusing the m2 slot pcie with standard pcie, nothing has to be stamped... Google it
The m2 slot will work as well.
What I’m confused about is what i wrote above. After sticking the wlan card i bought in the m.2 wlan connector on the MB, what next? All the cables i see are mhf4 (which go on the wlan card) to rp-sma which terminates in an antenna.