Nozzle extension ID plate. It reads
A Division of North American Aviation Inc.
Name: Nozzle Extension
Spec. No.: WT. 1616 lbs.
Mfgr: Rohr Corp.
Part No.: 209210 Assy. A 512 7
Serial No.: 8285565
Rocketdyne apparently had at least two vendors for nozzle extensions. This
serial number is earlier than other nozzle extensions which I've photographed
and was manufactured by Rohr Corp. Other nozzle extensions, with later serial
numbers, were manufactured by Precision Sheet Metal Inc. (e.g., the F-1s at the
Michigan Space & Science
Center and in the JSC Rocket Park).