How to find culture and publickeytoken of dll deployed on GAC

https://camerondwyer.wordpress.com/2013/11/01/how-to-find-the-version-culture-and-publickeytoken-of-an-assemby-dll-using-powershell/

Or use the SN tool in VS Developer command prompt.

If the assembly has been deployed to GAC, navigate to the folder containing the assembly and follow the article above, using reflection to load the assembly.