I had not seen this mentioned but for those attempting this strategy the following should be kept in mind. Once you find an aged domain that you like, make sure you don't transfer the domain to a different registrar. I've read that this is extremely IMPORTANT: the domain HAS TO stay with the SAME REGISTRAR to retain its age!
Xtro
No, the domain age is based upon creation date return from whois. Domains can be transferred to a different registrar, only the updated date gets changed.