I suspect they have the dashboard linked to the Cisco Parts database that CCW-R uses and vMX100s are not in there because they aren't hardware and weren't sold with individual serials. I suspect they never will be, although I'm sure the engineers could hardcode something so they show up.
If you found this post helpful, please give it Kudos. If my answer solves your problem please click Accept as Solution so others can benefit from it.