Yes, I believe the originals were done at lower cost , "Flash Chroming" over a nickle base.
I was told that the copper process was needed to clean up surface issues, prior to polish,
due to various surface conditions , caused by rust/dings/chrome removal , on these 40+ year old pieces of
stamped sheet metal.
**Also, the "Show Chrome" route is probably overkill for these covers , but they could not predict how
they would look with the lower cost option.