oldsewnsew,
OK, you got me. It sure looked like it had a top in the first pics.
Plastic gears and grease - I've had and still do have a number of Singers and others with plastic gears. With one exception; a Kenmore Sensor Sew 100, every machine with plastic gears had grease on the gears. Some was an amber color, some was icky black, some was whitish. But all had greased gears.
So, on those I've cleaned and serviced I use Tri-Flow or the white Singer gear lube.
Joe