Ballantine's fifth issue in 1988 (or 1986 - I've found conflicting info) had cover art by Michael Herring.  Sold as a boxed set with the Hobbit -   the  box is after the books.  I have also seen a copy of ROTK issued in black, rather than red.   The paintings are a bit odd to many, especially alien-Gollum and pope-Aragorn.