Issue with unzip command

I have a zip file on the unix server. when I unzip it using unzip command(unzip -q filename.zip) then the timestamp for the files less than 6 months to the current date are not retrieved instead It is setting the time as 12:00 AM to those files.
I have some operations based on the datetimestamp of these files and when I unzip the file,the dates for the files are retreived properly but the timestamp is causing an issue for the files less than 6 months to current date.Any help is highly appreciated .Thanks in advance

Regards,
K.K