Yeah, you should be able to upgrade your account if you have a valid serial number of a cisco device that is under a contract.
This is, as we mentioned several times in similar topics in these forums, why it's important to buy equipment that contains a current version. If you copy one from the other for educational purposes, fine that's up to you. I did that too in my home lab, but:
We do not tolerate illegal distribution of software in these forums (NOR BY PM), which includes Cisco IOS.