I started a thread a few weeks ago about my experiences trying to get backdating on a card I had in the 80s. I was initially told that Amex no longer backdates if the card has been inactive >5 years. I was later told they couldn't find my records. I was finally told that old records are archived and only the credit/collections department has access to records that old. CSRs couldn't see it. I eventually was told by a supervisor that he would send a message to that department and if they could find my record, I'd get backdating. I got the backdating (1988), so either they just changed it to get me to stop calling, or they found my record. If this is important to you, you will likely have to call several times (or your mom, really) and be persistent, but polite. Give as many details (what card, when opened, what used for, why closed) as possible. You can also search the archives for numerous other people and the strategies they have used.
I also asked (in 2012) for backdating of a card. I couldn't remember exactly when i had the card, and said it was somewhere 1986-1988, probably 1987. I quickly received a backdate to 1987. Since then, I think it was quite likely 1988, so I don't know if they skipped the research step and just put something in. I assume the CSR doesn't really care!
OK - was able to log in online and the account is set up. CL was $8000 so I am pleased. Again my average score is 720. However no back date ,it says member since 2013. I physically dont have the card yet but when it arrives I will call about back dating to 1991. I just shredded a bunch of old credit stuff and I know I had some old AMEX statements to give them an account number from way back then but oh well.