In looking at the documentation it appears the above question is no but I just want to make sure. Does the API allow for controlling the position of a camera PTZ or moving it to a defined preset?
No. What is in the pre-release is pretty much the same as the Configuration API. You can only read properties concerning PTZ Presets.
It is the plan that a future version of the REST API will be able to do this, but it is not possible in this pre-release version. Right now we are not able to say when a version that supports this will be released.
In order to trigger PTZ Presets, getting the camera to move to a preset, you will need to use other API for now.