I wonder if we should lose some functionality described in the Release Features when using Pega 8 and RM 6 with Robotics Studio / Runtime Proprietary information hidden? Or do you see any problem with setup?
Using a version of Runtime that old has not been tested with Robot Manager 6.1. I suppose you could test it and see if it works, however if it doesn't, you'd need to update Runtime to get support for it. Since that version is almost 18 months old, I would suggest you consider updating to a newer version.