Kosch company is still in business, they might have manuals.
I don't know what happened to my manual, I haven't seen it for years. They are a pretty simple machine. All the cutting parts are IH. The rest of it is stock bearings,seals and steel. The only parts that might be hard to fine/expensive are the yoke and the inner shoe that hinges to it.
The only thing you need to be concerned with right now is whether you got all the brackets etc. that mount it to the SC. I have bought several of these mowers over the years, and don't recall more than one that was ALL there.