Hiya Savedfrom...(What's your first name, bub?)
I must confess that I never really collected the set, and never noticed that card 163 Mel Roach was placed smack dab in the middle of the Los Angeles Dodgers numerical sequence---7 Dodgers before and after. That discovery is most fascinating.
According to Baseball-Reference.com, on May 9, 1961 the Milwaukee Braves traded Mel Roach to the Chicago Cubs for Frank Thomas, which I'm sure bears much weight in the explanation of why Roach is tough, though I'm still puzzled by his assigned number in the middle of the Dodgers.
As for number 193 Frank Thomas, he's with his fellow Cubs. However, it seems Post just kept Frank on the Cubs' send-away team sheet. As for his box card, it must have been deleted from the set, because the Standard Catalog has the cereal box Frank Thomas valued at $37, whereas the send-away card is only $7. (The values are from the long out-of-date 2001 Standard Catalog, but are relevant for the point regarding the disparity in value, which deduces that the Thomas box card is much much more scarce)
Then again, kids simply collected cards or teams; few would be brave enough to go for the entire set, so Roach having an oddball number may have been no big deal to Post. Maybe there originally was to have been another Dodger, such as Sandy Koufax! Wish Dan Mabey would come to our rescue on this one. Perhaps he knows.
--Brian Powell