Print and Web settings - Necessary to use both?

Hi,

I'm very new to InDesign, having only created one document in it ever. I now have (what I think is) a simple question.

I've just finished formatting a book using InDesign's print document settings, for the hard-copy versions of the novel I'm hoping to sell. However, the same novel will be available in electronic formats as well. Because InDesign has separate document options for "print" and "web", I did a bit of research on the subject and discovered that the only difference between them are the measurement settings (mm/inches vs pixels) and the colour swatch settings (CMYK to RGB).

My question is, to export the electronic version of the novel, is it necessary for me to make a conversion of the same document again under the web settings, or will I be fine exporting the file into an e-book under its current print settings? I'm unsure how InDesign will handle this sort of thing and would rather be sure than go ahead with the wrong choice. I'm also really hoping I don't have to recreate the same document again under the web settings separately.

Thanks in advance.