"Wabash Blues" was "probably the biggest hit of 1921-22, and Isham Jones' disc is said to have sold nearly 2 million" (Joseph Murrels, The Book of Golden Discs, London 1978, page 12).
The large number of pressings explains why we have two variants here. On the first B side, "Laughing Cornet–Louis / Panico" is split up over two lines, whereas the second variant manages to squeeze the entire phrase into a single line: "Laughing Cornet–Louis Panico."
I think that posting the source is the best you can do here, Xiphophilos. I've not personally had the opportunity to look over Laird's book. At nearly $185.00 plus shipping, I'm probably not going to anytime soon. (There is an Ebook version, for those who are into that, which is presumably cheaper.) If it matters that much, people can choose the source they trust the most.
I would agree that all of the proposed dates are essentially estimates. Rust would probably assert that he is confident that the date falls within the range he specified, but even Rust has been known to change his opinion in that regard. I suspect he would be fairly adamant about the location, too, but I haven't heard Laird's arguments and I'm not inclined to set anything in stone. I would note that Isham Jones' home base was Chicago and that it would have been easier and cheaper to record him there, but successful bands toured and almost always made it to New York as well, at one time or another. In the relevant time frame, Isham Jones had a very successful band.
I've made the source for the third date, ca. August 1921, visible in the Notes. It's Ross Laird, Brunswick Records: New York Sessions, 1916-1926, p. 88. In the end, all these dates are guestimates.
Opinions differ about these sides. Rust assigned them to a session in Chicago during the period September to October, 1921 in the American Dance Band Discography. (Even with Louis Panico's laughing cornet, the disc did not make the cut for Jazz Records, else we might have had a later and more definitive opinion from Rust.) The ODP (aka 78rpm discography) comes down in favor of October, 1921. With the above-stated location in NY and the date of c. August, 1921, we have up to three choices, depending on how much actual difference you think there is between Rust and the ODP position. Further input, anyone?