There is one document available named "Fastener_Assemblies_Best_Practices_v1" on GTAC download server. I am not sure if this is the same one with new name or similar to "Standard_Parts_Creation_Best_Practice_v1.1".
The "Standard Parts Creation Best Practice" document was never officially made available via the FTP server, or with the Machinery Library. It was an internal document intended to aid those creating the standard parts, but can be supplied by GTAC upon request. The "Fastener Assemblies Best Practices v1 document" is available from the FTP server: NX > Full Products > Windows (64-bit) > Machinery Library