Short answer: yes, you can substitute the rice solids for syrup. It is not a 1:1 substitution though. I don't remember the conversion of the top of my head but I know you'll want to use fewer solids by weight than liquid by weight. Rice syrup (or solids) doesn't add much in way of flavor. Basically just gravity points and probably a higher attenuation so it isn't the most crucial aspect of your recipe.
