Does the New Covenant require confirmation, the same thing the Israelites did when Moses with the twelve tribes of Israel confirmed the Covenant by acknowledgement and sprinkling of the blood?
The Old Covenant was dedicated by the shedding of animal blood and that blood being sprinkled on the people. This acceptance was only done once in the establishment of the covenant.
The New Covenant was also dedicated by the shedding of blood. "And for this reason He is the Mediator of the new covenant, by means of death, for the redemption of the transgressions under the first covenant, that those who are called may receive the promise of the eternal inheritance. For where there is a testament, there must also of necessity be the death of the testator. For a testament is in force after men are dead, since it has no power at all while the testator lives. Therefore not even the first covenant was dedicated without blood. For when Moses had spoken every precept to all the people according to the law, he took the blood of calves and goats, with water, scarlet wool, and hyssop, and sprinkled both the book itself and all the people, saying, "This is the blood of the covenant which God has commanded you." Then likewise he sprinkled with blood both the tabernacle and all the vessels of the ministry. And according to the law almost all things are purified with blood, and without shedding of blood there is no remission" (Hebrews 9:15-22).