No, the columns are not under separate selectors in the CSS. You could target the specific post in the right column, but the issue is that once you create a new post and that one is bumped off the right side and into the archive, that setting goes with it so to speak.
This is just one other thing I'll offer. Having the front page of your site nothing but links to other sites can possibly get your labeled as a splog (spam blog) by the search engines, and having so many outgoing links on the main page will seriously stunt your search engine ranking growth, if not completely kill it entirely. Search engines are looking for fresh original content, and a post full of just links is not original content.