The tarball was replaced on the developer's server on July 23, because the initial one have been built w/o the top level toybox-0.6.0 directory.
There's no code change, the ebuild is adapted to the 'broken' old tarball already. I see no need to change things again, it won't fix any issues except mild cases of OCD ;)
OK then. Personally, I used to employ ``emerge -f'' for downloading toybox tarball w/o figuring out its original location (while the latter is trivial, of course). And I've just downloaded 0.6.0 tarball this way and found that it's somewhat broken, and that it have been already updated on it's original location, so I've decided to report it—just in case.