The Sidcot suit depicted in the article is painted shiny, like leather As seen in the accompanying photo the suit outer cover was cloth. This was along the dungaree, or cotton canvas type, or any weave tight enough to cut the wind, so should be much closer to Matte finish. . .
Hhhmmm. . .it seems that is what the text say in the review. Berberry's gabardine to be precise. The figure does not look "shiny" to me but its just my opinion.