There would be no reason that I know of for there to be diffent part number. The floor pans are identical between the 2018 Sport and the 2019 N. WT needs to get it together.Picked up my 2019 Elantra GT N Line (Summit Gray) 3 weeks ago and ever since then I've been searching for an all-weather floor mat to deal with the rain here in Seattle. But apparently this car model is too new for companies like WeatherTech to produce a 'Laser Measured Perfect Fit' mat. WT offers one for the 2018 model but when I enter 2019, the only mat available was trim-to-fit.
Instead of ordering a trim-to-fit from them, I figured I'd support my local AutoZone and pick one up. So I grabbed a Goodyear mat for $39.99 in the hopes it'll last till WT makes a perfect fit. I've included pictures to give those searching for same an idea how they would fit. IMO, they fit rather well for a trim-to-fit alternative. Cheers!