The extra 24 hours that the NFL owners and players agreed give themselves to try to decide on an new collective bargaining agreement (or, more accurately, more time to negotiate another extension) will not change the free agency rules.
According to Adam Schefter, the extension is just a negotiating extension. The deadline to sign free agents, waive players, and conduct any other player moves that were permitted prior to the start of the new league year remains at midnight on Thursday. After that, no player moves will be permitted until the labor issue has been resolved.
The signing of O. J. Atogwe apparently will have to satisfy the free agency hunger of the Redskins fans for a while, perhaps for a long while.