I don't have that MAT.  That's the first question I asked DAZ when I got the M4 base.  They said that was the way the base came.  When I got the Morph++ I assumed a nude MAT would be included.  There was none.  I contacted DAZ again complaining about putting genitals on the outside of Boxers and they didn't even reply.  Is this a case of "Bug them til I get an answer"?