Here's a quick look at checklist #192. The three have different woodgrain setups. The first card (with comma) and the second card have what is seemingly the same woodgrain pattern, but under further scrutiny you can see that it is situated differently on each. The third card has a pattern nothing like the other two.
1962checklist192.jpg
Here's the comma vs. the non-comma differences. Watch the woodgrain area (especially the dark 'F' shape in the upper left) and see how the actual checklist itself shifts drastically up to the right. Since they don't share the exact same woodgrain setup, my conclusion has always been that the checklist with the comma was never actually 'corrected.' (It's important to note here that the reason this is relevant is because the straight, white top of the checklist card always aligns perfectly with the 'top' of the picture on the card next to it, so this 'proves' the comma wasn't simply eliminated in further printings. The card stands on its own.) It seems that they probably had checklist #192 represented a number of times on the print sheets and they noticed that one (some?) of them had the problematic comma showing, but it was too late and they never went back to correct the problem.
