This Page does say that 44303 was the last boat to be painted with the racing stripe and it mentions the episode of 'Lassie.' It also states that the Lassie episode aired in 1969. The
Eagle Page says that the racing stripe was painted on that ship in 1976. So it would appear that 44303 was the last 'boat', which is what your question asked, and Eagle was the last ship.
You got me on that one.
Father of
SR Powers, William T., S-178