The Carpenters Union Local 8 hand delivered a signed contract, complete with concessions, to leaders of the Pennsylvania Convention Center on Friday, but convention officials say it was too little, too late.

Convention center management had been feuding with the six unions that work inside the 679,000-square-foot facility nestled in the heart of Center City Philadelphia over a number of issues -- most notably Exhibitor Rights.

SMG, the center’s newly installed management company, and the Pa. Convention Center Authority wanted to relax rules to allow exhibitors do minor setup, break down and other installation work inside their own booths. The convention center put forth a Customer Service Agreement, which would allow for the changes, but the unions opposed concerned it could lead to less work.

Four other unions eventually signed the agreement, but the Carpenters Union and Teamsters, who operated vehicles, opted out, choosing to instead go on a short strike last week. Convention center officials said the chance to get in on that agreement expired on Monday -- meaning the other two unions are now locked out.

Despite the deadline, the Carpenters agreed to the work rule changes on Friday, signing the agreement and delivering it to convention center officials.

Carpenters union spokesman Marty O’Rourke tells NBC10.com the union was granted a 10 day extension -- giving them until Saturday at midnight to get the deal done. He says carpenters are ready to show up and work on Monday.

Convention Center CEO John McNichol says they’re not welcome because the union missed the boat.

“The Carpenters had every opportunity to be part of this deal and for them to feign consternation over the fact that they're not made part of it now is disingenuous,” he said.

McNichol said it was made very clear to the union that the deadline to sign the Customer Service Agreement was midnight on May 5 and that the Saturday deadline was simply for a different collective bargaining agreement that will soon become null and void.

"It was made abundantly clear to them, that the opportunity for them to join the deal was midnight on May 5th, so they had made the decision not to join on that process. So they're outside this deal, they don't have an opportunity to join in this process," he said.

The Carpenters and Teamsters will be barred from working at the Pa. Convention Center as of Saturday. McNichol says the work the two groups would have done has already been redistributed between the four remaining unions. O’Rourke said the Carpenters plan to fight the deadline.

Contact Vince Lattanzio at 610.668.5532, vince.lattanzio@nbcuni.com or follow @VinceLattanzio on Twitter.