As far as i know, you cannot change the way timestamps are being written into the packets by wireshark, since it always takes into account the system time.
since you already have a reference log and also know the timezone for the packet which you have to compare against, you should be better off modifying the packet timestamps matching to that timezone.
say, your computer time is in IST which is GMT+5:30 and the packet trace which you want to compare against is in GMT, then you can use editcap to decrease the timestamps of all the packets in your trace by 5 hr 30 minutes.
Hope this helps,
Sandeep Nitta