If you still have the .u file extracted from cache, you can use ucc.exe to generate ucl and int files for the .u file. Start up cmd.exe, type cd "(Path name to system folder of UT2004)" then type ucc.exe.
use ucc dumpint (.u file, has to be in the system folder) to make the .int files, and use ucc exportcache (.u file, has to be in the system folder) to make ucl files.
So if I have a Dualwield.u file, I first type in:
ucc dumpint Dualwield.u (Or ucc dumpint Dualwield, I forgot if you have to include the extension or not)
and then:
ucc exportcache Dualwield.u (Or ucc exportcache Dualwield, I forgot if you have to include the extension or not)
Done!