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We've recently migrated an old custom cms site to Umbraco at the same domain.
Google Webmaster Tool is reporting 1000s of "Not Found" errors from the old 404 page in the format
Does this mean that Google has historically indexed all these pages (ie before switching to Umbraco)? Searching for these urls produces no results.
Do we need to take any action (such as 410'ing pages which match this pattern) or will the new site returning a 404 be enough?