Dear Moshah,
the features similar to Bahu, Caping and Mata Ketiga Siva are found on other keris sheath then coteng's.
Bahu (if it means the small ridge at the bottom og gonjo and not simply Pidakan) is visible on the Cirebonese (?) sheath from Hidayat's page (oncemore
http://keris.fotopic.net/p56874076.html), Caping is similar to a common feature called Ri Cangkring, features related to Mata Ketiga Siva are Wideng on Javanese and Mata Ideng & Alis Pandji on Balinese sheaths.
The point is indeed, Sajen's sheath has no Loto or Pejetan and Wideng are very extensive.
The pictures are a keris from Banten (?) and Cirebon (?).