Blender 2.8 add-on RadeonProRenderBlender_2.0.1 installed successfully. Add-on active. Blender "System" reports "no compatible GPUs" under OPENCL tab.
I have tried this with both "Standard Distribution" from Blender and compiled Blender (latest version Feb 23 2019).
I have also installed Blender 2.79 with 1.85 add-on and it is detected cleanly.
This looks to be a "false positive" on detection during Blender initialization....ProRender 2.0.1 appears to be doing well for a beta! Upon further investigation ProRender Addon installed cleanly and is active/selectable in "Render" dropdown with Cycles and EEVEE. Metal2 appears functional and equal to or better than Cycles.
Thanks to whomever made this possible!