I think it may depend on the breed...but the particular breed I've drawn here does not. This one I picture as grey, darker than Cardassian skin usually is. It may be possible for them to be different colors, though.
The areas that don't look as though they have scales--I think it's different than, say, snakeskin...I've always imagined the "microscales" to be much smaller. If you tried to pet him and went against the grain you'd feel it, kind of like sandpaper.