Your front sight has been replaced with a Patridge (not Partridge) Target front sight.
Colt offered the Patridge front sight and the Elliason Target rear sight as an option on the Python.
When the factory installed these, they installed them as a set.
Often when the Patridge front sight was installed after market the standard Accro rear sight often had to be raised too much to get on target with the taller Patridge Target front sight.
Your front sight may have been altered to lower it. It looks slightly different then the factory original Patridge sight: