So even though the P/N are different, you confirmed fitment if 2019 rotor is a problem to fit?  Sometimes P/Ns change but no change in obvious design.  If the caliper is the same, or even mounts the same, uses the same pad, etc, there's only a few other things that would prevent a direct 2019 rotor swap, at least that I can think of.  Then you find some 2015 - 2019 rotors from a salvage, have them resurfaced, and problem solved....in theory LOL.