These TM's are old enough (1942) that they predate the use of FSN/NSN numbers. The part numbers in the manuals are just GM part numbers.
The links you sent are some of the parts I've run across doing searches. The trick is finding a matching set of pistons & rings that match the bore I have. I may have found a set in Europe that will work for the .020 o/s block. The other block is already at .060 o/s, which is the max o/s that were factory supplied. My only options there are find a set of .080 o/s rings that can be used with the EGGE pistons, or sleeve all 6 cylinders back to a smaller size that I can find a set of matching pistons & rings.
