There are a number of differences between -100 & 200 a/c, but they are externally very similar!
1. Higher fuel capacity due to larger CWT and extra reserve tanks for 2&3 main tanks. approx 20T extra.
2. Two APU generators on the -200
3. half pack setting on the -200
4. Bigger/stronger landing gear due to increased weights, also bigger wheels and brake packs to cope with higher speeds
5. Higher flap limit speeds
6.2 stages of flap load relief on the -200
and loads more stuff!
BTW, any 747 can have 2 or 3 autopilots not dependant on series.