Python/C API Reference Manual chapter 7.5 Other Objects does not contain subchapter for Class objects, but only Instance objects and many other are documented there. From header I can find that at least PyClass_Check and PyClass_New exist, I just don't know what those do until I take time to read source code... :(
Looks good for me. Actually the first pointer to new-style classes is the most important I think... :) (which I found out by myself after reporting this bug)
Actually one more thing: I think that chapter 7.5.2 Instance Objects would need also similar note about being relevant only for old-style classes. (At least I think it is only relevant for old style classes.)