Yes, that's right. The official opening is in two weeks, but it's rideable right now. (I guess they could close it again before the opening to complete the fencing, but it seems unlikely.)
Here's the opening announcement that was posted on various trail lists on Friday June 3:
PLEASE JOIN US TO CELEBRATE!
The opening of the newest section of the Great Allegheny Passage.
Friday, June 17, 2011 at 10:00 am
The amazing 3-mile section of the Passage includes two new bridges, a rolling ride along the scenic former U. S. Steel coke gas pipeline, and an exciting view of two of the Kennywood Park Coasters.
There will be an brief ceremony at the Whitaker Bridge to thank the funders, landowners, contractors, and volunteers. Bring your bicycle and ride the new section after the event.
RSVP to [admin followed by an @ and then the domain atatrail.org] or call 724 537 6905.
* Please enter at Guardian Storage (1002 East Waterfront Dr.
Munhall, PA 15120) and you will be directed to parking for the event.
The photograph below is a preview from the bridge across the Monongahela River to the Edgar Thompson Works of US Steel, the Whitaker Bridge on the far right, and in the center distance, Kennywood Park.
[The photo wasn't included.]