While most Mormon temples have historical artifacts placed in their cornerstones, several LDS Temples have historical artifacts on display.
I was walking through the Ogden Temple one day and right by the clothing rental I noticed a copy of The Book of Mormon on display. I believe it was a first edition, although it may have been a few years newer. I assume they will keep it on display once the temple remodel is completed.
In the Manti Temple there are many neat things to see such as the spiral staircases. One item that can be overlooked is a piece of temple clothing framed and hanging on a wall in a hallway. If I remember correctly, the item was from the 1850s. It is in the hallway leading from the recommend desk to the clothing rental.
The Nauvoo Illinois Temple was rebuilt in 2002. Both times that I visited it I asked the workers to show me what they could. They showed me the sealing rooms, baptistery, and assembly hall. They also showed me the historical artifacts that are now in the temple. In the recorder's office you can see a sword owned by Joseph Smith from when he led the Nauvoo Legion. The sword is engraved by him with his name, and also with the names of each person who owned it through the years. Eventually it was donated to the church and is now in the temple. This isn't the only artifact. The hallway north of the assembly hall contains several. There is a framed set of original keys to the temple. Several are replicas, but some keys in the set are the originals. There are also several pieces of framed temple clothing dating to Joseph Smith's time. I believe the first framed set belonged to Lucy Mack Smith, Joseph Smith Jr.'s mother. There is another piece of temple clothing further down the hall.
These temple artifacts are nice to see. I particularly like the old temple clothing as it allows me to compare how pieces were then to how they are now and determine what is merely style, and what is potentially significant and symbolic. It also let me see a way something used to be. I didn't realize we could use more white. I won't say more on that.
Do you know of any historical artifacts on display in temples? Please comment.