Thats wicked cool, and I have a lot of questions haha.
1.) For what purpose did you do this? Esk8 use? Audio? Some other application? Just for shits and grins?
2.) Is that just basic silicone that you injected into the mold? If not, what did you use?
3.) how did you get such a clean release from the mold with such a good surface finish? I would imagine that silicone would stick to a 3d printed part very well, as would a lot of other stuff.
4.) where is the injection point on this mold?
5.) STL’s? 
I hope you can answer some or all of these questions, cus this is a really cool proof of concept!