Not a clue.
Search for it at gunbroker.com and see if anyone's selling one there, and what the bids may be.
Forget what the seller is asking, that's not indicative of value.
Frankly, I'm not optimistic that it's worth much. There have been a lot of commemoratives like this, and most of them were rather poorly made.
Brass frame revolvers tend to be more poorly made than the steel ones. I say "tend to" because there are a few exceptions out there, but generally speaking brass-framed revolvers are made quickly and without the attention to detail that steel framed revolvers get.
Pietta used to make revolvers of terrible quality. Just junk. Then about 5 or 6 years ago their quality came up considerably. Not quite as good as Uberti, but darn near. I haven't looked over any Piettas for a couple of years, so I don't know if their quality has held.
When your revolver was made may indicate its quality.
The quality of the accessories will also affect price.
A bugle?
I have no idea how to put a value on that!
You'll have to search the internet to see what your revolver, accressories, box and bugle might be worth.
Just happened to think: Are you sure it is a working revolver? Many display revolvers like this have been made, that are completely inoperable. They're for show only. That would certainly affect value.
Let us know what you find out on its value. It's an interesting topic.