If you can get a developer to create a list of all the pages Google has crawled within a date range then you can use this python script to check if the page is indexed or not.
http://searchengineland.com/check-urls-indexed-google-using-python-259773
The script uses the info: search feature to check the urls.
You will have to install Python, Tor and Polipo for this to work. It is quite technical so if you aren't a technical person you may need help.
Depending on how many URL's you have and how long you decide to wait before checking each URL, it can take a few hours.
