I recently updated my book Whatever Happened to the Golden Plates? with some new info and links.
Tagline: Everyone wonders what happened to Joseph Smith's gold plates after he translated them. Using original sources, this book proposes a new scenario.
Here's the description of the gold plates in the Joseph Smith Papers.
It's always fun the way the historians cite this to support their claim that Joseph never referred to the hill as Cumorah. (Obviously, they could have cited D&C 128:20). And then they go to great lengths to point out that the description of the First Vision in this history was just a cursory overview which is why it doesn't have all the details of later versions. I agree with their take on the First Vision, but Joseph Smith omitting the name Cumorah from this 1832 history is not evidence that the name wasn't known before then, just as his omitting the details from the First Vision is not evidence that the vision didn't happen the way he later said it did.
Next they cite this one, published by W.W. Phelps in 1833.
In the year one thousand eight hundred and twenty seven, the plates came forth from the hill Cumorah, which is in the county of Ontario, and state of New-York, by the power of God.
(Evening and Morning Star I.8:57 ¶5)
Presumably they cite this one because it's the first extant published reference to Cumorah. But of course that's not evidence that the name wasn't known before then. In 1830, Oliver Cowdery and Parley P. Pratt were telling the Lamanites (their mission to the Lamanites) that the hill was called Cumorah by their ancestors.
"This Book, which contained these things, was hid in the earth by Moroni, in a hill called by him, Cumorah, which hill is now in the State of New York, near the village of Palmyra, in Ontario County."
Or, they could have cited Lucy Mack Smith's account. She said that the angel "the record is on a side hill on the Hill of Cumorah 3 miles from this place remove the Grass and moss and you will find a large flat stone pry that up and you will find the record under it laying on 4 pillars <of cement>— then the angel left him."
Or, they could have quoted D&C 128:20, which explains that Moroni announced the name of the hill while the book was "yet to be revealed," thereby corroborating his mother's account.
Glad tidings from Cumorah! Moroni, an angel from heaven, declaring the fulfilment of the prophets—the book to be revealed.
(Doctrine and Covenants 128:20)