Adding an HDMI Capture Card

Has anyone added a four-port HDMI Input to a Wirecast Gear 420?

I'd like to do so to expand the possibilities in my studio w/ the Gear420

I suppose a DeckLink Quad HDMI Recorder should be installable if there is an available PCI-E Slot is available where that blank is between the QuadOutput and the Quad SDI input. (See picture above)

I haven't opened the machine so I'm not sure yet. I thought I'd ask here first.

Any technical reasons I can't do so?

Thanks.