Yes you're right.
I did initial search before I entered the serial code and before I got to the wondercard,
the second search was when I get to the splash screen (with selection hovering at no, so that I won't accidentally collect it when exiting Gateway AR menu).
.
I'll try to do as per you suggested, seeing as this isn't going to be easy. Thanks ><
My best suggestion would be for test cases start a event that is easily reproducible like a Wi-Fi or Nintendo Zone one then
backup save
do the event
extract the wc6
restore the save to before the event
get to the splash screen
dump as much memory as possible
on a computer find a way to search in the ram dump for the wc6 data by opening the wc6 in another hex editor and copying a big block of the wc6 data into the search of the ram dump.
Note so the data matches up try to make sure both have the same date and if available on that Pokemon the same gender. So the data you search for will match.
alternative
For searching your way on the 3DS my only tips to look for and known values like the "wonder card id" and TID or SID of the event Pokemon which you can probably find through Project Pokemon if someone has already contributed the wc6 file.