Yes they will have - it should have come over automatically. (you might need to contact LIVECHAT to get it reassigned)
FWIW I don't recommend using ISP issued emails. They essentially trap you into using one ISP while the NBN now offers you the chance to get highspeed internet from any of them. Take the time to set up a free online email (gmail?) and its pretty easy to migrate emails sent and being sent to Optus across. Update your online contact details (bank, ultilities, facebook, etc.) and you can do it without hassle (the old Optus email remains in place while you do this). You also get better functionality like spam prevention and 2FA security etc.