Looking a little more deeply into this I discoved that there are some wing differences between the 200 and the 200 advanced.
On the 200 advanced, all the slats have two possible extended position. EXT which is a partial extension for flap selections of 1 to 10. At greater than 10 the LED's go to the FULL EXT position. On the earlier non-advanced models, only the outboard slat on each side had the capability of going to full extend position and only with flaps greater than 25°. I woould love to see a picture of this if someone has one.
Apparantly earlier basic 200 models had different Krueger flaps as well in that they did not go as far inboard toward the root of the wing as 200 advanced aircraft. On the 200 advanced, these flaps extend underneath the landing lights at the wing root instead of the earlier gap between the inner portion of the innermost Kreuger and the fuselage.
Can be seen here:
The Boeing 737 Technical Site