Cert-manager upgrade and restore

I am upgrading cert-manager from the 0.9.1 release to 0.12.0. I have read the docs at Rancher as well as the upgrade guide at cert-manger.io. The cert-manager guide says to back up your issuer/cert resources into a file and update the apiVersion as required, no issues there. However, when you re-install cert-manager, it creates a new cert-manager-webhook-ca certificate. Should I really be restoring the old one from my backup?

The guide for a 0.9.0 to 0.10.0 upgrade says you should delete those resources, as the bootstrap process has changed, so I don’t think I want to do that.