If you're talking about the flash hider, I totally agree!
One thing that may make the Thorens disc appear thicker, is the raised middle section would be making contact with the scope bracket, I feel like I'm seeing a shadow there, in between the disc and the bracket, in the photo of the real prop.
Yeah, maybe. My instinct is only based on the fact I didn't notice such a gap when comparing the thorens to the spacer below. Coulda missed it.