My old account is still reporting as a Paid Charge-off.
When I first received the Optima, I asked if they would remove the old account. The rep I spoke to said that she did not believe it could be removed, but wasn't 100% sure. I've been meaning to write a GW letter, but haven't yet. I'll let you know if it works when I do.
I did notice that after receiving the Optima, the drop-off date for the old account was shortened by 6 months. Thought that was odd, but I'm not complaining.

I'm pretty happy that I took advantage of the whole deal. Positive tradeline, positive back-dated history, and now a CLI. Amex definitely makes me nervous with all their recent AA, but perhaps I can stay under their radar.
Good luck with your card!