Originally Posted by Marcus
"The scabbard is in kojongan or kekojongan style from Bali/ Lombok, but apparently more frequently used in Lombok."
I see that in “Kris and other Malay weapons”, G.B. Gardner identifies this as the Madura type (Figure 13)
Marcus, though Gardner was an important figure in bringing the study of keris to light in the West he is not always 100% accurate in his writings.
The Walikat sheath form can be found in Jawa, Bali (though more often Lombok) and Madura, but it would be incorrect to identify it as solely a "Madura type" and i don't believe it originated in that location.