I think in this case it didn't even rise to the level of archaelogy or artefact. Anthon, after asking where the characters on the paper came from, was told they were (basically) something a religious nutter had made up, and he asked for the certificate back, realizing his ego had overstepped its bounds and he didn't really recognize the characters, like an authority should who was talking to these country bumpkins and their accidental discovery of some old document.
It's kinda funny, the way it's described in the JS History. He tried to extricate himself from the mess as soon as possible, but it was too late. He'd been fooled, and they used his initial certificate as "proof" ever since. It's now become basic canon in the church history.
Also, keep in context that JS was a treasure seer by trade prior to using that trade to find his plates and translate them so to start a new "correct" religion.
But did he actually produce any treasures? It's my understanding he bought into the whole buried treasure fantasy going on in the area and that he tried to insert himself into the mystical side of it all, but he wasn't producing any artifacts or anything useful to sell, and was more on the fringes hiring himself out either for physical labor or a bit of mystical stuff, without much, if any, real financial gain. So it's not like he was bringing up a string of religious artifacts and selling them.
Again, my memory is old and rusty on this--do you have anything on whether or how much he was making on this or what he was producing artifact-wise for money?
But after the Anthon incident, it's all religious, with the angel taking stuff back (as I recall--need to recheck) until Mormonism and dime museums intersect again with the Pearl of Great Price, when what goes around comes around and Smith gets pressured the same way, forced to "translate" the museum owner's papyrus or lose his ego standing as a great translator of ancient religious texts.
I believe this is a much more detailed pro-Mormon site, going into detail about the translation methods and how Smith used aids but then eventually didn't need them:
http://en.fairmormon.org/Book_of_Mormon/Translation/Urim_and_Thummim
As I recall--geez, now you're gonna make me look this up again

--there was a colonel so-and-so who started a dime museum traveling, or perhaps stationary, in the Utah area in the late 19th century, when any town of any size had to have a dime museum in it, and he had a lot of early Mormon "artifacts" though none of the original angel-touched stuff that would contract the stories of what was taken away.
I'm going to be lazy and not corroborate this, but the following site says Joseph Fielding Smith, whom Mormons would rely on, claims the urim and thummim went back with the plates:
http://askgramps.org/4692/what-happened-to-the-urim-and-thummim-after-the-book-of
"Joseph Fielding Smith, in his Doctrines of Salvation, 3:, p.225, says 'We have been taught since the days of the Prophet that the Urim and Thummim were returned with the plates to the angel. We have no record of the Prophet having the Urim and Thummim after the organization of the Church.' "