Could be and probably is a fakeout. Tellem just wanted to put Seldon through that to wring whatever she could put of his mind. So in that sense the deathbed flashback trope was actually a literal plot point. It wasn’t just us seeing those things, but Tellem. Maybe she’ll learn something that changes her mind about Seldon.

In fact, I think whoever gave him a body again did it for exactly this purpose. A holo-Seldon would not have been vulnerable to Tellem, and thus wouldn’t have succeeded in eventually winning her over. The whole resurrected Hari gambit is a strategy to win over the Mentalics.

Plus if they really were going to kill Seldon (again), they wouldn’t have used it as a cliffhanger. They would’ve just killed him.