PEP 3147 says[0]:
"""
For backward compatibility, Python will still support pyc-only distributions, however it will only do so when the pyc file lives in the directory where the py file would have been, i.e. not in the __pycache__ directory. pyc file outside of __pycache__ will only be imported if the py source file is missing.
"""

Does that mean that there could be cases where untagged pyc files are used in 3.2+?
In that case the patch should be ported to 3.2 and 3.3 too.

[0]: http://www.python.org/dev/peps/pep-3147/#rationale