Should I verify user token after login?

[tal-rofe]

I use the "passport-google-oauth20" package and I have set the credentials I need and the redirect callback.
Everything works fine, in the callback handler I do receive the tokens and the profile as well.

One thing I cannot understand - do I need to do an another step manually?
I mean, in further steps of using this package, should I follow this guideline which guides the developers to locally verifying the user token?:
https://developers.google.com/identity/sign-in/web/backend-auth#using-a-google-api-client-library

Or, it is implemented out-of-the-box?