version number is stored as a string inside "SV.T" file inside root of media.pk2.
"SV.T" is blowfish encrypted with the key "SILKROADVERSION" of which only the first eight bytes are used thus resulting in the key "SILKROAD".
the file is 1024 bytes long; all space after the string containing the version number is filled up with NULLs.
proof of concept to create a faked SV.T file (you can import the generated file into media.pk2 with pk2tools of pushedx afterwards):