1967 was about when mono lathes began to disappear. After that time, even "mono" records were cut with stereo lathes with different shape cutting styli. My two mono cartridges reflect that change as well. My older Denon 102 is a conical stylus and plays old mono lps in a smooth and forgiving way. The Benz is a modern line contact styli. I can get a clean sound out of a pretty banged up older mono lp compared to a later stereo if it was cut with a conical cutter. And it affects my record buying. I stay away from buying anything stereo below NM-, whereas I'll go down to even VG in old mono.
There may still be a few of those old Scully/Westrex lathes, rebuilt a time or two, still out there cutting away... but they've got to be ancient.