I've done a number of RetrObrite projects and never have had to remove any of the stickers/emblems and no harm was done.
The only thing that was effected was any sticker that had its information typed/rubber stamped on a paper sticker. That type of inked just seemed to wash away and the paper dissolved. Plastic stickers on my A4000's and A500's did just fine.
These are my opinions only and of course do this at your own risk.
