tar restore file ownership

Hi, I have and old tar archive I want to restore. However, I notice that directories from the tar archive are created with the current date and owned by root:root - I'm running tar as root - whereas the files (not directories) are restored with the original permissions, ownerships, and dates. I use "tar -xvzp -f archive.tgz" for restoring. Is that normal? Am I doing something wrong, or was the archive created without ownership information for directories? If it is, as I think, that the tar archive does not have that info, what option, if any, should have been used to create the archive originally? -- Cheers, Carlos Robinson