I received my new American Express TrueEarnings Costco Card last week and after researching backdating on myfico.com I called today.
I spoke with a very nice young lady in the replacement card department and simply explained to her that I would like for my account to read that I have been a member since my original date, 1987 or 1988. She put me on hold for a couple minutes, came back and said congratulations! It was backdated to 1988 when I was in college. She thought it was hilarious as she was born in November of '87. She explained that she filled out and submitted a form for my card and she also completed one for my DW, who is an AU.
Thanks to everyone here for sharing your experiences.
My Wallet: Capital One $673, Barclay's Apple $2k, Amex TrueEarnings Costco $6k, Chase Freedom $5k, Discover More $15k