An Iron Python implemtation of this: http://chillijam.co.uk/2006/05/04/determine-if-an-assembly-is-a-debug-or-release-build/

diagnostics.py

import System

def is_assembly_debug_build(filename):
	"""Returns true if filename appears to have been built in debug mode"""
	result = False
	dll = System.Reflection.Assembly.LoadFile(filename)
	customAttribs = dll.GetCustomAttributes(False)
	for att in customAttribs:
		if att.GetType() == System.Type.GetType("System.Diagnostics.DebuggableAttribute"):
			result = att.IsJITTrackingEnabled
	return result