OP, if your account was locked, it must be for a good reason. I doubt they would exempt you from that proof of ownership unless it's under some special circumstances, especially since I would suggest you to try to find the relevant private keys since Bitcointalk's IP logging policy would probably have removed the IPs you used from years ago by now.
Even if the IP logs were kept for that long, I don't think theymos would have shared this information with the account recovery team
(three people from the Cryptios team are responsible for account recovery). And as far as I know, the account is automatically locked out if you tried to restore it with a security question. Even if you remember your password, someone else could easily try to use this function
(which could also lead to blocking).In any case, if the OP remembers the password and he still has access to the e-mail linked to the account, he will not need to sign messages. Just need to wait for a response, but do not forget that active links also do not last forever
(if you missed the moment, you will have to send the request again).