They could never hide them completely; they just did their best to ensure that they are not super intrusive. Having also seen a very nice looking '97 ESB print, the matte artifacts can definitely be quite noticeable, but like everything else, it’s a balancing act to keep the film on the whole looking polished and the FX shots go by quick.
The common complaint among FX folks that matte artifacts were more visible on home media transfers remains true on the whole: think of the bright, milky black levels of the first Star Wars VHSs, for example. However, I think that sentiment got overstated on these boards some years back and treated as gospel.