There is another variant not mentioned yet. I looked at my "assembly line" valve on my original engine last night. It has a .020 wide "v notch" cut into the "points" of the hex area half way up the hex.
Like this one/style? Forms sort of a "diamond? look on the finished product Have seen that style many times
Picture from a magazine article. Can't tell the version/style but IMHO something caught the sunlight just right part way up the side of the PCV
Service replacement example/part
Don't know if its the cutting depth, tip of the cutting tool or angle while looking at it without having them in hand next to one another. Have pictures with this cuts into the hex area through 67 versions but each looks similar but different in ways
Could post but not sure it it would help