Nope, it looks like sys.platform will refer to any modern Windows as "win32", even if it's a 64-bit OS running 64-bit Python. In general when you're programming in Python you're unlikely to need to worry about whether the machine you're executing on is using a 64-bit or 32-bit OS. If it is truly necessary for some reason, there are other ways to get information about your system, including a lot of functions in the platform module.
import platform
print(platform.architecture())
print(platform.platform())
print(platform.uname())
print(platform.version())
print(platform.release())