I'm not sure how strict the quadrajet numbering gets in the later years. I'd be shocked if everything else, including year manufactured, matched the original engine application except for the division. I would bet that carb is the original for your engine. My truck has a 17080213 and is an original 1980 K25 with a 350/TH400/NP205. According to the "numbering guide" my truck should have an even number as the last digit since it is an automatic truck. This is the correct carburetor for a federal emissions M engine code truck though.
The GM instruction sheet that came with my quadrajet rebuild kit shows a 17085215, 226, 227, 230, and 231 as being original equipment carbs for a 305H engine in 85-86