Many vehicles don't have "OEM" hitches. Especially cars.
@gmb3 It looks like the hitch uses those internal nuts that get fished through the frame. Since those probably aren't getting re-used, you may want to purchase a set of them for the install. If you look in the instructions they may list out a separate part # for a kit for those.
Hitches are cheap. I would look on E-Trailer and see if one of the other hitches than the one you have in-hand are easier to install. They often have multiple designs, some easier to install than others. Their site is definitely the go to on information. If there's a better/easier to install hitch buy it as opposed to trying to re-use yours.
A quick look, only the expensive Ecohitch doesn't require drilling though. And that one typically requires full bumper removal and it's actually expensive..