More than likely, yes it'll install those language files associated with that program in the Update. You can reinstall it and see. DeLocaliser from Bombich (Bombich right?) doesn't take that long to run does it?
When I Installed Tiger, I deselected the language file and most of the printer drivers and saved close to 2 GB of disk space.
It's better not to install them in the first place, much cleaner. When I get a new system, what I do is make sure it works, then I reinstall leaving out the stuff I won't use. (This includes not installing classic.)
Besides saving diskspace, not installing the language files drastically cuts down on the number of files on the system disk and by extension noticeably cuts down on the time it takes to repair permissions.
Plain text compresses well. Language files are pretty much plain text. In theory there might be enough space in the 10.4.3 update, but only if there wasn't much actual code.