Hi,
CUWL Pro supports Webex Meeting and Webex Social by default while in CUWL standard , it is Add-on.
Since you have 1000 CUWL Pro , so , 1000 users would be entitled for Webex.
you can also refer the ordering guide for more details which says
All existing UWL Professional users on Cisco Unified Communications 9.0 or later with active UCSS and ESW coverage can get the WebEx Meetings Server software and license by following the steps below. For more detailed WebEx Meetings Server migration instructions, refer to the Cisco WebEx Meetings
Server product ordering guide.
1. To download the software, access the Product Upgrade Tool (PUT) and order the WebEx Meetings
Server product migration SKU of MP-WMS-MIG= or MP-WMS-MIG-AU-K9=.
2. To request a license, contact the Cisco Global Licensing Organization (GLO) to receive WebEx
Meetings Server licenses. You will receive an email with more detailed instructions.
http://www.cisco.com/web/partners/downloads/partner/WWChannels/technology/ipc/downloads/finalcopy.pdf
regds,
aman