Technically, the sale itself is not being registered, just the ability of the buyer to legally buy a pistol. I'm sure the local sheriff keeps track of how many permits are issued to someone, but the system does not keep track of how many permits are actually used.
Once a pistol permit is used, it stays with the seller. In the case of the FFL, it gets stuck in the bound book for eternity. For a private sale, the seller can keep it for his records.
And, as Firehawk mentioned, having a CCW negates the need to have the purchase permit, so a CCW holder can go out and buy as many handguns as he wants to with his CCW and nothing gets back to the sheriff on it.
Yes, it is a Jim Crowe holdover, but it's what NC has for now and probably for a long time to come.