MSE8000 is a chassis, not a specific MCU blade. There are a number of different blades you may have in it.
That said - I have an MXE8000 with a 7010 - Telepresence Server blade, and I have Room Kits of all types that can connect to conferences on that MCU no problem. If you're talking about an image in the GUI to represent a connection, I'm sure that won't be in there since the software you are running on whatever blade you have is probably much older than the Room Kit, but that doesn't mean it won't connect and work, that's just an icon.
Yes, the RoomKit devices will work fine with an MCU.
Are you able to provide a better description of your issue and include the version numbers of the MCU and RoomKit software you are using (it's recommended that you update to recent software versions if you haven't done so already).
Wayne -- Please remember to rate responses and to mark your question as answered if appropriate.
Wow - that's some old code, it's no wonder you aren't seeing icons for newer systems. The last code upgrade for that was over four years ago, and that was 4.5(1.72) - yours isn't even posted anymore.
That said - I'd still expect it to work, but keep in mind that is a standard definition MCU, not HD, so don't expect high resolution. If memory serves the 8420 can do 720p but only at 15 FPS. Otherwise it's w480p I believe, so it won't look great especially on larger screens.
The 8420 has been end of support for well over a year - you should start planning to replace it - if it breaks you will not get any support from Cisco. If you want to stay on premise CMS is the way to go. Cisco did have a pretty good "trade in" deal for customers like yourself, but they may or may not still exist - it's definitely worth exploring.