dsc73719.jpg

Three ID plates, as seen between the legs of the gimbal actuator arms on the left of dsc17023.jpg.

The top plate is the engine's "master" ID plate. Although most of the pre-printed lettering on the ID plate is illegible, the plate reads

Part name: Rocket Engine Assembly
Contract No.: NAS8-5604
Part No.: 104001
Spec. No.: R-1420eS
Stock No.: [blank]
Serial No.: F-4028
Model: F-1
Accepted: [blank]
Weight: [blank]

The two smaller ID plates are the "MD identification plate RD171-1022-0001," used to indicate what "MD change" (engineering/configuration change) incorporated into the engine.