No, it means the script will call the python interpreter in /usr/bin/python when it is run.
From the CLI you can execute it by:
The chmod has only to be done once. Or you can do:
chmod 755 thescript.py
and you don't need the chmod. Naturally, substitute your directory names and script names in the above, and not blindly use my names.
If using the GUI, you can make it executable from your file browser (which effectively does the chmod) and then click on the icon to run it.