Da página do manual do wget:
--no-use-server-timestampsDon't set the local file's timestamp by the one on the server.
By default, when a file is downloaded, its timestamps are set to match those from the remote file. This allows the use of
--timestampingon subsequent invocations ofwget. However, it is sometimes useful to base the local file's timestamp on when it was actually downloaded; for that purpose, the--no-use-server-timestampsoption has been provided.
unzip também tem uma opção -DD para ignorar a restauração de registros de data e hora dos itens extraídos.
De man unzip :
-Dskip restoration of timestamps for extracted items.
Normally, unzip tries to restore all meta-information for extracted items that are supplied in the Zip archive (and do not require privileges or impose a security risk).
By specifying
-D,unzipis told to suppress restoration of timestamps for directories explicitly created from Zip archive entries. [...]The duplicated option
-DDforces suppression of timestamp restoration for all extracted entries (files and directories). This option results in setting the timestamps for all extracted entries to the current time.