I remember not giving it much thought at all until (I think) the episode Brothers
, when Dr. Soong opened a panel in either Data or Lore's face. Bear in mind I haven't seen it in years, and don't own any of the series and can't check, but I remember the face panel as being a (for lack of a better description) weird Texas-ey shaped thing that had to have contradicted earlier depictions. Seems like they could have used something in-stock, which would have been both consistent...and cheaper!
Mind you, I'm not a micro-continuity person, and I never lost sleep over this stuff, but for some reason it crossed my mind again.
Also, now I'm wondering if that kind of Data-stuff fell under the jurisdiction of makeup, or props?