I didn't get a PM and I thought the question was interesting so I just reached out to my friend. In Moore terminology, "spotting" is that final pass that other people often call flaking. He told me they used spotting templates--pieces of thin plastic that fit the tabletop and had parallel grooves cut into them. The scraping hand followed the grooves with his spotting tool. I've seen him do the spotting before, but not with a template. He uses a long-handled scraper with a narrow carbide that's almost dead flat on the end (but with radiused corners, of course). Sounds like you had to have years under your belt before you'd be allowed to put on the final touch.
An aside: when you see the tools Moore used (and uses) to achieve its famous accuracy, it's somewhat shocking because you look at their tools and think--"This is the same stuff I have." The scraping hands are known as "geometry men" in the factory and becoming one is a big deal. It's their skill at taking measurements, making corrections, over and over and over that leads to the final result. There is an attitude of total dedication to refinement and also a sense of appropriate pace on the floor; building machines at Moore is a marathon, not a sprint. To give numbers to this, if I recall correctly, it was expected that a geometry man would require about 120 hours to establish straightness and perpendicularity to the required tolerances of just the x- and y-axis ways on the B18 and G18 machines.