This movie completely ignores the fact the Seavers sold their house in New York to move to Washington, D.C. at the conclusion of the series, and the fact that the previous reunion movie took place in the Washington area.
Obviously Maggie was not elected to Congress in the first Growing Pains movie.
Tracey Gold came back for this last episode even though she was still ill from anorexia. Notice how during the final scene where the family sits in the bare living room eating pizza, Carol doesn't touch it.
The theme song to the Growing Pains spin-off Just the Ten of Us is playing in the backround as the Seavers watch television.