At the time Blockchain.info did not require an email address or any other type of identifying info. Blockchain.info used an alias identifier to recover the wallet ID
Don't they have a support? I mean, if you remember your alias identifier and password you can send them a message. I don't think that email would matter that much. If you successfully get your bitcoins back, which is difficult since these guys know what you have, don't dare to leave them 5 whole bitcoins. 
I went back in 2013, yep they had that option back then:
If you get the chance to talk to the support, show them this.