tar question

I have a JAZ disk that gives me the following output

meg:# tar -tvf /dev/sda
-rw------- root/me 39413440 2000-09-27 21:13:59 main_backup
-rw------- root/me 123847437 2000-09-29 20:15:19 main_backup
-rw------- root/me 123229961 2000-10-04 03:12:59 main_backup
-rw------- root/me 91681727 2000-10-05 21:50:06 main_backup
-rw------- root/me 78710337 2000-10-07 19:03:42 main_backup
-rw------- root/me 157035028 2000-10-11 00:39:49 main_backup
-rw------- root/me 140819753 2000-10-14 16:30:01 main_backup
-rw------- root/me 167477405 2000-10-18 15:37:46 main_bkp

I seem to recall a cronjob, years ago, that I had write/tar
these files to the disk with something like 'tar -rvf /dev/sda main_backup'
(I can't recall whether I used the 'u' flag or the 'r' flag.)
Either way, how can I extract the file 'main_backup' only for a given
date (e.g 2000-10-07)?

v/r
-Mike