Let me put this on my list and see what I can do for printing! Shoot me a pic and measurements of what you've got (if anything)? Thanks!
Big OOF. Those tiny parts are hard to print in a way that will fit properly in the Kato locations... KAto sells the Passenger Car Details here and you can use thin nstiff wire to replace the Kato pre-bent piece
There is also this: Gold Medal Models N 160-26 Kato Smoothside Passenger Car Details (Enough for 8 Cars) Wolf