AoS Rumor Engine Seraphon???

I had been thinking the samething. They are just different enough that it might not be Troggosths though.

 

At least not the parts of them we can see. The scales visible on the pictures seem more angular, not that round.
Might still be scales from their backs or so, I haven't seen any pictures yet that show the troggoths from behind.

So yeah I tend to say those are not Troggoth scales. But they might be.

 

Yeah, the Troggoths look more like cracked rock than scales, but you never know what their backs might look like.