To see if it was a false prediction we only need to see if the same prediction would be made today.
Tiktaalik roseae, better known as the “fishapod,” is a 375 million year old fossil fish which was discovered in the Canadian Arctic in 2004. The prediction at the time was
Once we have researched all the fossils relevant to the water-to-land transition, we begin to get an idea of what timeframe this transition happened in. We know the lobe-finned fish are from 390-380 million year old rocks. The first tetrapods appear around 363 million years ago. Common sense tells us that the transitional form must have arisen 380-363 million years ago.
In order to find our transitional fossil, we’ll need to find rocks that are between 380 and 363 million years old. https://tiktaalik.uchicago.edu/meetTik.html
However since then
The oldest evidence for the existence of tetrapods comes from trace fossils, tracks (footprints) and trackways found in Zachełmie, Poland, dated to the Eifelian stage of the Middle Devonian, 390 million years ago. Tetrapod - Wikipedia
So if the prediction was being made today they would say " In order to find our transitional fossil, we’ll need to find rocks that are older than 390 million years . Hence they wouldn’t have been looking in the strata where Tiktaalik was found.
The original prediction would not be made today and thus it was a false prediction. Like I said, it was a lucky accident rather than a successful prediction.