I don't even know what's up with the disc generator tool in the labs toolset right now, there's two versions of it on the github page:
https://github.com/sideeffects/SideFXLabs/tree/Development/otls/disc_generator.1.0.hda [
github.com]
https://github.com/sideeffects/SideFXLabs/tree/Development/otls/disc_generator.hda [
github.com]
But the one that loads by default seems to have fewer features since the vertex color is missing.
I dunno if there is an easier way to switch between them but you can just get rid of the current definition. Go to wherever the SideFxLabs is installed on your machine and in the
SideFXLabs-Development\otls folder, delete / move the
disc_generator.1.0.hda folder. Assuming you have the previous version in there (the disc_generator.hda folder), close and relaunch houdini and it should use that version of the tool which includes the vertex color and whatnot, I assume that's the one your course is using.
PS: Best of luck in your vfx course! : )