You're probably not surprised but I don't believe you either.
Actually, I bought it in 2015.
There's no way to prove that you bought it in 2015... You did not post until May 2023.
This user was one of those who left during the MT GOX exchange incident in which many members departed from the Bitcointalk forum.
There were a few MtGOX "incidents" -- the exchange was open for business as normal in Oct 2013, the month of the original owner's last post. Bitcoin broke $1k for the first time in Dec 2013. In early 2014 it was reported the exchange had suffered another hack, and then it declared bankruptcy in late Feb 2014. So the final "incident" occurred 3-4 months
after the original owner's last post.
However, it should be mentioned that in those days, there was no merit system thus a statement that buying a ranked-up account is not true.
It was a ranked up account, though. It had enough activity to be a Full Member:
https://web.archive.org/web/20131010181157/https://bitcointalk.org/index.php?action=profile;u=103790And having an age of 10+ years makes it all the more valuable... Although I always have a hard time believing anyone from back then is interested in participating in bounties now.
I have another account which is used exclusively for taking part in bounty programmes started in 2022. As far as I know, it is possible to use two accounts in this forum until something wrong happens.
Sure, until you get caught scamming or cheating, then you may find yourself going back to one account.