My oath invite asked me to bring the invite itself, two IDs, COPR, PR card, and all passports.
At the oath ceremony they checked the invite and one ID at checkin. Then they checked the invite again and the PR card, and then took the PR card.
No one asked for or checked passport or COPR.
This, so far as I have observed, is the typical way it goes.
And that was how it went for me. Indeed, I had my passport in hand along with my PR card, and the individual who took my PR card said that was all they needed.
BUT as others have astutely observed, it is best to follow the instructions, and the instructions (at least usually) state that the individual scheduled for the oath needs to bring essentially the same documents as applicants are instructed to bring to the test and interview, at the least to bring the applicant's current passport and PR card.
It warrants noting that how it TYPICALLY goes is not how it necessarily always go. It warrants noting that it is quite possible for the personnel doing the check-in at the oath ceremony to perceive a reason to verify the citizenship-candidate's identity, in which case the presentation of a passport can be important and perhaps necessary.
If the candidate is asked to present a passport, the candidate has NO excuse based on others saying they did not need their passport, when the candidate received written instructions to bring the passport.
The tendency to infer what is OK, what the rules are, based on other people's personal experience, is one fraught with risks.
If in doubt, follow the instructions, and otherwise, yep, follow the instructions. Those who elect to overlook the instructions do so at their peril.