Yes. I've read the same article. No. That is not the original Lewis air rifle. Everything changed with publication of "A Journey through the West: Thomas Rodney's 1803 Journal from Delaware to the Mississippi Territory" Here's a review:
https://scholarworks.iu.edu/journals...ew/11775/17257
From Rodney's journal, it is absolutely clear that Lewis is operating a Girandoni type airgun. This was the premier air rifle available in the world at the time. They were made in abundance, as was Lewis's, in London. The airguns made by Lukens pale in comparison. For a wonderful example, see the Staudenmayer in the Milwaukee Public Museum. This Staudenmayer is exactly the same as that seen in Baker/Currie Austrian Military Air Rifle M-1780. Of course, what Baker/Currie do not understand is that the gun they examined and reported so well is the product of English manufacturing, so, their title is a bit off. However, the gun was designed in Austria by professor Nemetz and was used by the Austrians.
So, bottom line, Lukens is out of the running.