Yes, and the upvoter would not know either way

The idea is that curators will know beforehand what percentage a post will give them and they will then vote accordingly.
Say for example a new talented author want to build up his reputation and is more interested in the attention the post gets than the actual rewards. This author can chose to give 100% of the rewards to curators which will draw a lot of voters to it ( only if they are aware that the post will give them 100% of course)