These are common concepts for Standard Service Graphs and Service Graph Redirects. Service Graph with L4-7 Device in Go-To mode == L3 Service Graph. L4-7 Device in Go-To mode and the SGT has PBR enabled == L3 PBR Node.
Concepts
L4-7 Service Graph
requires the Service Graph Template
Service Graph Contract
aka SG Contract The contract associated with the Service Graph.
Service Node
referrs to one concrete device. In Cisco litterature the term Service Node is used more than Concrete Device.