Hi, I can't confirm if dielsiana is self pollenating, I don't have that species yet, but if it is, yes self pollenating means you do not need to do anything and the seeds will still form and be viable, heck you can even forget about the flower and eventually you will find new seedlings in the pot. But if you want to collect then just wait till the flower bud turns brown then you can collect.
Congratulations on your flowering drosera and good luck with the seeds.
Oh, actually if the seeds are small enough even if you collect them chances are some seeds will still fall and germinate in your pot, so you get a pleasant surprise anyway.
TTFN
Arvin