IIRC, there's no way unless you remember it or try to prove the ownership through Coinbase's representative if they allow so. But too bad that they have tons of inquiries which is making each of those inquiry to be delayed. It's said on their website.
We’re currently experiencing an increase in inquiries. There may be a delay in responses from Coinbase Support. We’re committed to doing better. We appreciate you bearing with us during this exciting time for the cryptoeconomy - we’ll reach out as soon as we review your case.