From my vantage point, it is an original enlisted tuchrock with original Major's insignia added. I have still not made up my mind on whether it was done post war or not. I would like to see more photos of the tabs and the other shoulder board, where it is seated into the shoulder seam. I would also like to see a photo of the underside of the collar, to examine the placement of the collar cord.
I have seen photos of officer's wearing the Tuchrock in the "field", so I can definitely seeing a frugal officer wanting to save his tailor made tunic for formal occasions and having a few enlisted types made up for everyday use.
Thus far, the main thing I do not like is that the collar tabs do not seem like they have been on the tunic for a long time... but it could just be the angle I am seeing.
What is the asking price?