Build Unreal Engine on Linux behind a firewall.

I’m trying to build Linux in Centos behind a firewall, and basically tried doing almost the same step’s as this guy mentions:…letely-offline

For me it looks like the UnrealVersionSelector file doesn’t seem to exist, am I missing a step to generate those files? Furthermore I didn’t run “gitdependencies.exe” is this necessary If i just downloaded the source?