The 92 Kx250 came with a plated cylinder from Kawasaki. With the bike being 18 years old I am sure the bike has had someone in there & maybe they put a steel sleeve in there. You need to check to find out. You can pull the exhaust & stick a magnet in there & if it sticks well it has been sleeved if not it's plated (which you can have replated / I think plating is better).
Hope this answers your question!
DoldGuy