Add OEM navigation to Tuscon without GPS/screen

Hi there - tried a few searches, but nothing that matches perfectly.

Just bought a 2013 Tuscon GLS with the simple radio/XM/Bluetooth headunit. Is it possible to just buy a OEM navigation headunit (I see a couple on eBay) and plug that in instead?

Wondering if there are some pieces missing? e.g., GPS receiver etc.

Thanks,
Adam