Throughout the past, Hamas has always refused to accept Israel's right to exist. They agree to cease fires so that the wounded and dead may be removed, as well as redeploy their fighters and rocket launchers.
So, if they actually agree to Egypt's peace plan and recognize Israel's right to exist, that is a major step forward and just may end all hostilities.
However, the most likely action will be that in writing, Hamas accepts the terms and Israel's right to exist, then claims that renegade elements of Hamas are subsequently the ones firing rockets at Israel, claiming that there will always be criminal elements that want war.
One must keep in mind that Israel is an "infidel" nation in their midst and Islamists really do NOT like that.