After even more research, looking through all the files I've got, my notes, and so forth, that particular prime is one of about 400 or so PRPNet primes that were manually put into the BOINC database before I did the mass import. The bottom line is I have no idea what the origin of that prime is, who put it into the database, and whether or not this was found by the same person as is listed in the Top 5K database.
Please do not PM me with support questions. Ask on the forums instead. Thank you!
My lucky number is 75898524288+1