Yes, the user has to have HHS installed for DS mats made with HSS to work.   However - because it came with the Elite skins almost everyone has it.

It is possible to make HSS mats save them, duplicate the folder and edit the files to use the uber surface that is included with DS3.  DS3 free version can read and use them that way.

To do that you have to save them as .ds or .dsa, saving .dsb is not editable in a text editor.

To make the conversion search for: support/omnifreaker/shaderDefinitions/surface/omHumanSurfaceDef.ds

and replace it with: support/DAZ/Uber/shaderDefinitions/surface/omUberSurfaceDef.dse