Not necessarily, but there are a few things that you need to make sure of:
- The page should be using the proper semantic elements. This means things like header, nav, aside, etc.
- All headings and page content should flow in a logical order. H1 > H2> etc.
- Without styling, elements should still be in the order they are intended to be read or listened to. Any meaningful content should retain its meaning with CSS turned off.