Yes, I believe that all current Kato passenger car lighting kits are made using LEDs Currently Ver. 2 is the best one (ses brighter LEDs and revised design of the light diffuser). I don't think Kato sells any of the incandescent ones anymore.
As Craig mentioned, they use a single LED (light engine), and the diffuser distributing the light over the length of the car. But some still find it not optimal, and they build their own lighting circuits using inexpensive LED strips, bridge rectifier, resistor (and capacitors to reduce possible flickering). Benefit is that there are multiple LEDs over the car length, so the lighting is more even.
The original incandescent, and also the first generation of Kato light units used a diffuser which was even less useful for evenly distributing the light through the car. I suppose you could reuse the original light diffuser and just replace the bulb with a home-brewed rectifier, resistor and a white LED.
We had a thread about this about 10 years ago (time sure flies!), and it was actually you Craig! Do you remember? You built those light kits using my recommendations, and were quite happy with them. See
https://www.therailwire.net/forum/index.php?topic=29654.0 Less expensive than the Kato units too.