04' Prius information screen help

Hey all. I got my hands on my first Prius and I'm looking for a bit of help. The current information screen installed is a non nav unit as far as I can tell. It's also broken , but still usable(someone pressed too hard so colors are all off). The steering wheel has controls for "map", "phone end" and "phone call" but the screen doesn't respond to them. I'm wondering if maybe the screen was replaced? I would like to buy a nav unit in there.. is there an easy way to check if it's compatible? Thank you so much in advance!

PS; love my first Prius! Had to replace a cell and recondition the battery, but 400$ for the car is an awesome deal.