While I agree the chrome carrier has a replacement key I would note that a chrome carrier with a Parco-Lubrite (unplated) key can be original.
The change to Parco-Lubrite from chrome for the carrier and the key was sometime after the beginning of September 1965.
This change was to be "without obsolescence".
As an aside, changes in parts under Government contracts were done one of two ways...."with obsolescence" or "without obsolescence".
With obsolescence means that on a certain date (or serial number) the old part was not to be used and all remaining old parts were obsolete and not to be used in further production. Only the new part was to be used and all old parts were to be scrapped or in some cases held for repair parts.
Without obsolescence means that all the old parts were to be used up before the new part was to be put into production of the item.
As the carrier and key changes were both "without obsolescence" if they ran out of chrome keys for chrome carriers then the Parco-lubrite key would be used until all the chrome carriers were used up...then all carriers and keys would be matched .
This of course works for the Parco-Lubrite carrier with the chrome key as well and this combination is also possible.
In either case......I would recommend that the key on the chrome carrier be removed and the screws replaced as you can see they have been "buggered up" by some "Primitive Pete" with a tool that did not fit. I would be hesitant to use this bolt as it cannot be taken for sure that the screws were properly tightened/ torqued when it was assembled to the carrier.
Better to be safe than sorry.
Jim Gilmore
Jim Thorpe, PA.