I was able to determine the reason why the older runtime was used.
The quick fix was to symlink /usr/bin/python (which was originally 2.7.2) to /usr/local/bin/python where the newer version of Python is making /usr/bin/python also 2.7.3. Upon restarting Apache, 2.7.3 was used meaning somehow /usr was being used over /usr/local. However, I didn't want to stick with this as the solution, so I removed the symlink.
After some further digging, I looked at the apachectl script and was able to determine that it was loading environment variables for Apache from /usr/sbin/envvars
I modified the following line of the envvars file to include /usr/local/lib and restarted Apache. It loaded with Python 2.7.3 (thus solving a separate issue with _uname I was having with Django that is caused by 2.7.2/2.7.3 discrepancies)