http://www.daystarweb.com/productdetail.php?productID=22 - specifically calls out DS and DT trucks.
Also, I can tell you the RLs are identical to the naked eye. I wish I would have snapped a picture of the top hat in their 2019 kit and the top hat in their 2018 full lift at Summit Racing a couple weeks ago as I live a hop-skip-and-a-jump away (went there to compare control arms in the kit and purchased a set of blems for cheap). I can't tell you why, I can only say that my feeling is they've decided to market the kit differently for the new model year and new gen and include the control arms since that was a known issue in the past with lifted trucks. Want an easier install, here - you have to take these control arms too. Who knows. Call these other companies if you need to truly make sure you're buying it for a 2019 DT truck.
Also, when you say a lot of sites will say 2019 because they mean 2019 Classic - I find that to be the opposite. I've found that most sites only call out the 2019 when they mean the new 5th gen, and that they specifically call out "Classic" or "Old Model" when referring to 2019 4th gen trucks