I may be able to shed some light on that; somewhere around the mid-to-late 2000s something changed either with how PDGA measured discs or maybe the plastics that Innova used for discs and discs that previously would've measured 2.0cm started measuring 2.1cm, 2.1 became 2.2 and so on.
If we look at the list of PDGA approved molds with 2.0 to 2.1cm rim width and measure them we get these results:
Mold | PDGA rim width | Measured rim width |
Wraith | 2.1 | 2.16 |
Invictus | 2.1 | 2.07 |
Mamba | 2.1 | 2.05 |
Mystere | 2.1 | 2.02 |
Starfire L (SL) | 2.0 | 2.04 |
Monarch | 2.1 | UNKNOWN |
Beast | 2.0 | 2.04 |
Monster | 2.0 | UNKNOWN |
Starfire | 2.0 | 2.07 |
Orc | 2.0 | 2.05 |
As you can see they're all in the 2.02-2.07 range aside from the Wraith, which is the only 2.1-measured mold on that list from pre-2010 that I have actual measurements for. So if anything the Mamba and Mystere are the outliers in being called 11 speeds.
The Mamba and Mystere are both very shallow and understable molds that fly quite far for low effort, which might explain them being marketed as 11-speeds. Also, the Invictus was originally billed as an 11 speed before being changed to a 10 speed. Regardless, I think it's likely that the Gorgon fits better in with 10 speeds based on its rim width, though the distance might be similar to that of the Mystere and Mamba if it is quite gildey and understable.