BT, Julia Auctions has been selling two very large collections of Kentucky Rifles since last fall. There are huge numbers of pieces in each collection, and a major collector passed away recently, and his pieces have been sold, or are in the process of being sold. Hence the rich market in these guns, but prices may have been depressed a bit as a result of so many things becoming available in a relatively short period of time. Julia will have another auction soon on the Serkin Collection which is so large that it is being sold in three segments. I think that the next one at Julia will be the last one for a time. In the meanwhile, other pieces continue to show up in more localized sales and auctions. For selective buying, this is a very good time.
There is nothing wrong with the three guns that you have found and shown photos of here. Could use more photos of the first gun, but the second looks correct to me and was made by Nicholas Beyer near Lebanon, PA probably around 1825. This appears to be one of his later guns as it has some 'creative' artistry. A nice piece, nonetheless.
The half stock is quite correct and is representative of the McCammant family level of work. You can find some photos of their rifles in Jim Whisker's, (author), books on VA, WVA, and Ohio gunmakers. These are generally available on the usual book sellers lists. It would seem that this one you have found is better than the average though it appears to have a walnut stock.
Whisker has books on the Lancaster/Lebanon schools and you will find good photos of Beyer's work as well as rifles by other prominent makers of those times. "Thoughts on the Kentucky Rifle…" by Joe Kindig is a good source, too.
As you delve into this world you will find that it is as complicated as the coin world, if not more so. Have fun!
I can't speak to the claims of your dealer contacts, but frankly, I doubt it. I know the most promnient dealer in the trade and he tells a different story, but…who knows. Ask a realtor how business is and the answer is always "Great, couldn't be better!" while he slowly packs up to go to the poor house.
Dick