Check what kind of hardware slots are available linux
I think this will do it:
sudo dmidecode --type connector
For me, it shows a lot of ports - masses of USBs, a Firewire, ESATA and SATA connectors etc. I expect it will show an m.2 port - although it might have a different name - for example, my Firewire shows up as P1394.
If you're interested, here is the output for me, and here is the output for just sudo dmidecode.