Consider at least keeping a logo in a corner, or perhaps as part of a title bar on each slide or a few key slides (title, intro, outro, first in a section). It makes it seem more official (should be a minor thing, but can be impactful depending on the audience). When presenting to peers, my simple presentation slides were appreciated and accepted. When presenting to management or other teams, I had to make those additions or it was thought of as a draft or hastily assembled.