Yep. I needed to do valves and guides in one of my K301's less than ten years ago, the original 1963 engine out of an IH Cub Cadet 123, and all parts were easily available. Loved that I could press new guides in and hand ream them, by comparison to the Kawasaki V-twin I rebuilt this summer, which could only have the heads replaced when the guides slipped.
Then again, the Kawi V-twin is overhead valve, and makes more than twice the horsepower at a similar weight and smaller footprint, so there's something to be said for new technology.
I think one thing we keep stumbling on as a society, is that we tend to compare very cheap new stuff to much more expensive older stuff. I suspect these American made Kohler's of the 1960's and 70's were very expensive by today's standards, when scaled for inflation. And we can still buy very good and expensive engines today, Honda GX or my Kawi V-twin.
But then people look at a crappy B&S or Tecumseh, and say "they don't make them like they used to". Bull! Someone still does, but you bought the cheap alternative!