Spray painting will always have an overspray that will cover everything with a fine coat of paint dust - not a good idea in a darkroom.
Would you do it in your kitchen? No! Then don't do it in the darkroom.
You are probably quite correct and Fixcinater's sanding is also not a good idea. However, if you are not precious about prints (only reproductions from negs) then it's not a big problem and the dust will settle.