The reason you have all those multiple files is because of the sticky bit set

Actually, S indicates (in this case) that the setuid and setgid bits are set AND that the file is not executable by either owner or group. The sticky bit governs certain access permissions for "other" (or "world") and is indicated by a t or T in the mode string. And none of this really has anything to do with "immutability" of files (which is governed by write permissions for the files and the directory they are being un-tarred to).

See man pages for chmod, sticky and ls for the full story.