Okay, Rob, remember, this is filtered thru my brain, which distorts everything...
With the great Firebaugh, it's all about ideas, and how things work and what to achieve. With the early tables he wanted to address warped records, and decided on the acrylic that was dished in the middle, which also meant a clamp to get it snug and the warp out. Hence no mat. Now, years later, different thinking, different ideas. Flat platter, hence the mat , sans clamp. The geometry of the arm allows for improved tracking on its own. And as everyone can attest, usually sails thru a warp. The dished platter had issues with regards to the entire record surface. New platter does not.
So, haven't tried it yet sans mat, but I'm thinking it is there for a purpose. We'll see/ hear.
One thing to note , try putting a mat of various makes on the older dished type- bleh! It ruined it.
If you get to try one of the Auditoriums, either the thinner $99 or the thicker felty $300, I think you'd side with this side of the pond. Your worries should be all about your mains...

Isn't that what Limmies worry about most?