I can say with certainty that feature will not be on US models. It's probably aftermarket even in Korea. The trunk has conventional arm-type hinges with struts to hold it all the way open (same as the simple ones used to hold up the hoods of many cars). The latch and actuator are normal as well. No motors or anything out of the ordinary that I can see.
One interesting thing I noticed tho, and it's off topic, but like the 09 Sonata, the Genesis Coupe does not have a key cylinder for the trunk. The only way to open it is with the transmitter or the switch inside the car, so if your car dies or the actuator craps out you will be locked out of the trunk. I don't think that's very smart. Anyway just figured it was interesting enough to mention.