[RSSSL78]

I have some of these wheels also. What I have been told is they are service replacement wheels. Any wheels that have another number after the K18 or K19 are service replacements. Was told KH made these wheels all the way up to the early 90's. All the ones I have seen have a 5 after the K19. Don't know about the center lug stamping letters. The originals had just the K18 or K19 stamping there, but not all I have seen are stamped there.
John