The Gold Cup #51 guide with 1/8" post has been added to the chart.
Based on the fact that we actually see it in a package, I'm wondering if the guide with the 1/8" post wasn't the *real* part number 51, and the guides with the .177" (4.5mm) post (which we do not see in packages) aren't some other, later part number...
Although I am not, other folks seem to be interested in pickup guides introduced after 1969. So, I went downstairs to my secret hideout and dug out some 1970 and later guides I had hidden there.
What I found are repackaged Jet Flags and (congrats to Gator Bob) AJ's guides:
First, a yellow Jet Flag repackaged by Cobra:
Next, orange Jet Flags repackaged by REH:
Last, off-white AJ's guides repackaged in what *might be* a Riggen header card. I don't know who originally sold the orange AJ's guide (maybe AJ's?):
Gator Bob: Is that orange guide the color AJ's guide you have?
For what it's worth, I also have a small ziplock bag of loose Jet Flags in both white and 5 other colors, and *not one* of them has a mold number higher than 4.
I found no Steube UltraGuides... Somebody find or shoot some photos please!