I'd say that bit's even more interesting than the bit you bolded, Grond. I can't recall whether or not the Dwarves in The Hobbit said anything, but I know Gimli told Legolas that the Dwarves of Erebor did help in the delving of the Wood-King's halls. He said so during his description of the glittering caves of Aglorond.
In any case, I think the Wood-king in the halls delved by the dwarves was one of the stronger ties between the Sil and the Hobbit- I was going to mention it for your discussion with Walter on The Hobbit forum.