That is what they said in the email. I also went to one of their monthly events they have at House Wine on Barton Springs and they said the same thing. They also said they would like to add a restaurant level and observation level at the top so it might be higher than the 655 they said, but that they weren't sure if they would be able to add it or not.
If anyone is interested they have a social gathering at House Wine in South Austin on the last Wednesdays of every month. When I went it was pretty cool. Lots of interesting science talk and other fun and interesting discussions if you enjoy itching your inner geek occasionally like I do.
Also House Wine donates 10% of the night to the planetarium.
Also up in North Austin on the second Tuesdays of every month they have their monthly fundraisers at Opal Divine. I haven't been to that one as that far north may as well be Canada for me.