If a motherboard specifies being a K9 AMD product, it’s Socket AM2/AM2+. If it’s K8, then it’s going to be a Socket 939, maybe Socket 748–but that would have an opening in the center of the socket where there aren’t any pins.
Never heard of a AMD Socket 748. Theres really no K9, Socket 754-939 and AM2 are K8 and AM2+ are K10. Even though 754-939 and AM2 are all K8s there pin layout make all of them incompatable with each others Sockets. AMD AM2 and AM2+ have the same pin layout but one is K8 and the other is K10 architecture.