I've seen the CRL for S2 and i've seen the preliminary CRL for the Daimyo Fett. The material for the S2 looks quite different as it has a tighter weave and does not fray the same. S2 mando and Daimyo have quite a few other differences. The kama Boba wears in BOBF is the same material he wore for his tusken robes. It looks to be closer to a linen or cotton than a silk, as any raw silk i've found is too thin.
The MMCC CRL also only say "Cotton or Silk weave". Which is helpful, but is similar to saying "Its a Toyota Sedan". Theres many different types of cotton or silk weave but from what i've seen on Dented Helmet, 501st boards, MMCC boards, Reddit, Boba Fett Builders on Facebook, and in the Bounty Hunters Guild, the actual material was made specifically for the show and is going to be extremely hard to find.
I do believe that the closest match is a cotton slub weave with a silk layer underneath.
I may be wrong and i'm very open to being shown proof, but as for now i see it as being a different fabric.