While messing around with the small radiator leak today, I wanted to take out the stat to make sure I didn't plug it up with them-seal. I noticed immediately it looked a bit different inside. Instead of the 4 small metering holes, it has 2 larger ones. Also, the other side looks a bit more robust, and it seems to open a bit wider.
I tested both, and it opened faster and flowed better than the oem unit with the tea kettle test. It is stamped inside with 82C for the temp, but I couldn't find any name or model. The number on the outside is 99628 but searches came up with nothing. The previous owner said he had the stat replaced a few months back.
Anyway, I thought it might be useful if someone knows which it is, as a side by side test vs the OEM proved superior. Also,the oem is brand new...only used it for a week in the other rig before going to the grey soft spring one. I was going to swap the grey one in, but thinking now don't bother. I like the 2 hole design, and less likely to get plugged up too.
Here is the comparo between the two:

 

I have noticed that motorad tstats have the internal stamp, but I don't think they only have two metering holes. Interesting observation.

 

My motorad warm weather thermo from Atlantic British looked like the 2 holed one

My temp stays around 203 fully warm.