An example:

richard@omnis:/home/richard$ python2.7
Python 2.7.11 (default, Apr 27 2016, 04:35:25) 
[GCC 4.9.3] on sunos5
Type "help", "copyright", "credits" or "license" for more information.
>>> from ctypes import *
>>> from ctypes.util import find_library
>>> find_library('magic')
>>> cdll.LoadLibrary('libmagic.so')
<CDLL 'libmagic.so', handle fe240840 at fe7879ac>

Finally, as you can see above, LoadLibrary() works fine to load '/opt/local/libmagic.so' because of the runpath in the python binary, but find_library() does not because the runpath is ignored.

This should probably be considered as 'unexpected' behaviour.