I also got caught on how GP said Season 5 which would have been from the 60s, not the 2000s. But apparently it is correct (unless you want to be pedantic about the choice of word Series/Season).
And they started renumbering at 1 for 2023-2025 when it went to Disney Plus (to onboard new people and because they don't have rights to older episodes.)
The listing of seasons on Wikipedia goes:
Season 1-26 (1963-1989)
Series 1-15 (2005-2025)