Please make the revision history of help center articles public to all users. When a non-moderator tries to access the revision history of a help center article (example), this is shown:
I really don't know why revision history of help center articles are hidden to non-moderators. Since non-moderators can see the revision histories of election nomination posts (example), the tour page (example) and policy locked posts (example), I don't think it makes sense to hide the revision history of help center articles for non-moderators.