My opinion is no, from experience and buying many hundreds of used WSOP sets when they were Kem Plastic. Kem plastic is not plastic at all and is a mixture of cellulose (PAPER) and acetate (PLASTIC). It makes a Kem card very thin with a snap that no all plastic card can have. The drawback is that the paper in it will make the card warp.
Only thing you can do when you gat a new set of Kems is to keep pressure on the top card of each deck (thick cardboard the size of the cards will do it then rubber band the box and top. They did have Kem Weights at one time when the Bellagio demanded them as I was told. I bought the rest of the weights and since sold them. The weight was a thick piece of plastic.
All plastic cards also have their drawbacks, they are easy to dent with a fingernail. That is why it is impotant is you are at a high buy in cash or tournament game you change the cards often. Why because people cheat. I can testify I have sorted through hundreds upon hundreds of sets and some sets have the same cards dented in with a fingernail from both decks in the set. yes people CHEAT especially when millions are on the line. The Kem card is very hard to dent.
Do yourself a favor and throw the warped and bowed cards out. You want a WSOP 2012 set Used but in nice shape let me know Jim I will send it to you gratis. These were all PVC plastic. They are from Fournier the sister company of USPCC they were made in Spain.