I have a 1990 kh-41. Its prety low hours 1600hrs yet a little work horse. Can get into prety tight places and still starts on 15f* mornings.
I see no major parts that have been replaced. I did change a drive motor seal. I believe it still has the original fan belt and see no signs of cylinders being repacked.
It was prety neglected when i got it. 4 or 5 zurks didnt takr grease, swing bearing grease hose was broke so that wasnt either. Rad full of dirt and fluids/filters of unknown age.