I also am on an n810. Just tested, and it is the same for me. A couple of days ago I noticed a link on the facebook home page "click here to download a bookmark for your n810". It wasn't in the ads off to the side, and upon clicking it, it opened a page stating that they did not have any downloads for my device.

Thanks, Fbook.

It would seem that facebook id's mozilla mobile as (surprise) a mobile browser, and redirects to the m.facebook site. Although I haven't looked into it, I'm sure there is a way to spoof (useragent switching) the site into allowing you to go to the version you prefer.