they probably used aftermarket DID's aswell, but the Moto X fox RM preparation book i have only mentions Suns. i would have genuine perod fox RM pics in that book or in a fox catalogue or on computer somemwhere.
that bike just looks like a replica Scott Stegar built from parts.
im pretty sure Fox had their own swing arms too so you might not have to have a Thor
i was just reading that book and not all the Fox 125's has Simons forks. some riders still used the stock ones and modified the std forks with Simons or Fox fork kit. Mark Barnett was one of those