IIRC, and this is foggy memory, the big changes between model years are engines (6 cylinder Continental on older, 4-cylinder Lycoming on newer)
Correct.
and recommended flap settings for take-off (no flaps older, 10 degrees flaps(?) on newer).
For normal takeoffs, it's zero flap in all older, and "zero to ten" in the book for later models, although nearly everyone teaches and uses zero for normal takeoffs in all models. For short-field, the book flap setting changed from zero to ten between the 1979 and 1980 model years, for reasons that Cessna Technical Support is unable to explain, and which is kind of confusing since they are both C-172N's. For soft-field, it's always been 10 degrees in all model years.
Carb heat is a bit more important on the Continental birds than on the Lycoming birds, but I believe both call for carb heat "ON" at reduced power.
This is true. The Continental's carburetor body is thermally isolated from the crankcase, but the Lycoming's is bolted right to it so it picks up a lot of heat transfer, keeping it warmer and reducing vulnerability to carb ice. However, the checklist still calls for full carb heat in all models at reduced power setting.