TOF, I agree with what you say almost 100%, that is why I initially avoided even mentioning the possible monetary value of the lock, too many variables and it is always hard to get the right price. Anyway, even though the cat is out of the bag now I still would rather not give my "opinion", because that really is all that it is. And your friend and I would get along very well unless he and I got in each others way over a "deal"....
To be honest, when I checked Lodgewood's price on the mainspring, I was quite surprised that it was as low as it is but then realized that occasionally some of the percusssioned M1816 locks are broken up for parts, especially if the lockplate is badly pitted or other parts are missing. Their prices are overall fair and their experience and willingness to help buyers/collectors/shooters is exemplary in my opinion, they are good people.
Back when I first started dealing with early US military guns (40 years ago) there were still stocks of spare parts for the 1816 and later muskets available for sale and you could assemble a percussion version for around $25. Sadly those days are gone, but even in the late '60s a nice original flint 1816 lock would sell for over $100 in, as you say, "the right circles", and sellers wisely waited until they went to the right show before they really tried to sell them - they have never been common. As late as 1985, I let a friend beat me out on a clean, uncut M1816 barrel, original flint condition with an excellent bore and no external pitting for $35 figuring I would pick up "the next one" when I saw it. I'm still looking, especially at that price....
