BVRAAM,
Open source data such as that found in Wiki are all you’ll get (or again, should get!). One very good reason for continuing to protect such data after a piece of kit is retired is that the data could serve to prove the credibility of sources who may have leaked information while the kit was still in service. As those sources may still be active then there is a clear imperative to avoid corroborating their earlier tales. Or, indeed, to avoid exposing sources of deliberate misinformation!