PS. also I think the cards might seem thicker because well used and played with cards (dirty), the paper may "fluff up" a bit from handling IMO. The paper stock of CJs is a porous rough textured paper similar to a thin construction paper. Most/Many E145-2 will not have the staining because they were obtained as a complete set from company, while all E145-1 cards were obtained from the boxes of CJ.
Id think the higher grade/clean cards were stored in a way to keep them pressed and thus they might seem thinner??
Thats the only thing I can think of on why well used worn cards might seem thicker.
Another example.... Well worn R319 Goudeys always seem thicker than the sharp clean NRMT ones.