Thank you to Experius.nl for their most excellent Magento 1.x patch helper which helps you find files in custom themes, custom modules or local overwrites that also might need to be patched manually. It saved me hours with SUPEE-9767. Anyone have a time machine so I can use it on the previous 10 patches?

https://github.com/experius/Magento-1-Experius-Patch-Helper