Single "character" or "named" models that are fully painted to a quality level DO sell.
The "pro-painted" descriptor on eBay (re: wargaming miniatures) is flooded with both swirly and very highly talented individuals, buyers have to wade through them to locate the truly "excellent" ones.
For THIS model, there is a couple of rubs, I think.
#1 This particular Librarian, despite it being a named character, was mass produced with a set. You can find him for around $1 USD-$3 on eBay in bare plastic by himself, even though "Librarians" in 40K are supposed to be very rare, elite, hero-types.
#2 PLUS he is "cast" to only go with one chapter, so the market is limited to players that play THAT chapter. If it was a more "generic" Librarian painted to this quality, your potential market is increased TREMENDOUSLY.
Would this one in particular sell? I'd say depends on your asking price. Best way to find out – locate a 40k model that is similar in rareness and painted to about the same quality and put it on your watch list, if it sells, you know the target price now, if it does not, you might need to price yours lower than that.
