Nice pickup. I have that one myself. Really annoyed I didn't jump on the "cream" one when I had the chance. Did you get it from Cabourn direct or maybe Rakuten? Fit is Authentic line. I went with my usual 50. I'd say it's simply a CPO shirt. You can wear it as a jacket, but it's not that thick if you ask me. I wear it over a woven shirt. I could see layering it yet again with some over that if you can make it all work.