Now, if you're one of those people who got hold of CK 1.6.91 and put it aside for whatever reason, that MIGHT work because it was using those new subrecords. I can't vouch for that though since I reverted to 1.6.89 when 1.6.91 was backed out.
P.S. Come to think of it, I think I did try forcing the issue early on in the beta, just out of curiosity, by hex editing the Update.esm internal version number. If I remember correctly, CK 1.6.91 would then attempt opening Update.esm, but with many errors. So, it is quite apparent, that the incompatiibilites are more than skin deep.