Yikes - sorry I wasn’t getting notifications about replies. My apologies for the delay! Thanks all for your feedback - I have a couple updates.
First, and most importantly - the dealer I traded with to acquire it informed that before selling it he had two experts take a look: Rafael Eledge (Antiques Road Show) and Shannon Pritchard (Old South Military Antiques). The consensus was that it was very old, and either an early reunion flag or possibly from the war itself. Definitely not a reenactor flag or modern reproduction.
I also had it black light tested and nothing illuminated, which furthers the case that it’s quite old. Another resource said this type of flag was given early on in the war to some of the units prior to swapping for other flags later on. Maybe it was just brought out for use at Jenkin’s Ferry for one reason or another? Who knows. But it does seem to be old and genuine to the period.