No, Plo Koon does not appear in Star Wars: The Acolyte. However, a member of his species, the Kel Dor, does appear in episode 4 as part of the Jedi expedition to Khofar.

If Plo Koon had shown up in The Mandalorian season 2 finale, then it would have been a major reversal of established canon, revealing that the Jedi Master didn’t actually die in the fiery crash ...