While the 52 mantle gets 10 points and the 51 bowman gets 9, you will note that some of the tougher cards like the Briggs Meat (9), all 3 stahl Meyer (8), home run Derby (7) Yoo-hoo (8), Tip-Top (8), the Venezuela cards, etc are weighted extremely high. Compare that, for example, to the iconic 56 Topps which is weighted at a 4. I suspect they weigh the importance of the card as well as rarity.
https://www.psacard.com/psasetregist...position/13018
Chuck asks a great question. No, I do not believe that the card is added to the registry by mere virtue of having have been graded by PSA. However, PSA does welcome suggestions regarding which cards should be added on to these master sets. If you can get it into a psa holder, you then need to argue your case I guess.