It has to be. If Pelagius was 25 when he took the throne in 3E 339 (when his aunt, Empress Morihatha was assassinated), that means he was born 3E 314.
The reason for this error is because the Morrowind version of Brief History of the Empire, Book IV, says that Pelagius died in 3E 388. One person thought this meant he lived to be 74, and a second person knew the age, but not the date. So he counted back 74 years from 3E 368, which would be 3E 294. This has had multiple contradictions in the lore, and created some confusion on the page itself.