P. m. PIMBURA and P. molurus molurus: differences

[Seba]

I am an italian herp writer and I am searching if there are true differences between Python molurus "pimbura" and Python molurus molurus. Yes, I know that pimburas are not considered a valid subspecies and are identified as molurus molurus, anyway are there some differences? Someone told me that pimburas have only two postoculars, while molurus molurus from India have three postocular scales: is it true? Is there a good article or book that speaks about these aspects?
Thanks a lot
Stefano Barone