well, i know that the clock are just images in framework-res in the drawable-xhdpi folder. Shane is prob right in regards to the date in layout.xml of that same file.
give me a second and i'll find the date colors. i found where they're called in but there wasn't any type of identifier for the text color

edit: alright, it took a lot of hunting around to figure this out haha looks like Shane was correct after all.
res\layout\keyguard_circlelock_clockwidget.xml
change (line 21)
<TextView android:textSize="20.0dip" android:textStyle="bold" android:textColor="#ff
f6f7c9" android:gravity="bottom|center" android:id="@id/zzz_date_month" android:layout_width="fill_parent" android:layout_height="24.0dip" android:layout_marginTop="2.0dip" android:shadowColor="#aa000000" android:shadowDy="
2.0" android:shadowRadius="
1.0" />
also, the AM/PM color, i think that is line 18 of this same file as android:textColor="#ff
f8f8f8"
edit: and the shadow can be found with this AM/PM line for it, respectively. for this one, you'll need to change shadowDx and shadowDy, as well as radius to 0.0. that'll get rid of shadows