Hi Michael,
It's only a gut feel that these kerises are 'off-Palembang'. The reason being I've not seen any particularly "high" or "refined" form of such keris forms. In addition, they have this 'kampung' quality and variation in styling which I associate with satellites of centres of power. The "variation in styling" being that they resemble Palembang kerises, but not quite. The strongest connection to Palembang comes from the hilt, which even in itself is varied. An archetypal Palembang hilt of this form would look like this:
http://www.kampungnet.com.sg/modules...view_photo.php
A slightly off-Palembang keris with similar hilt would look like this:
http://www.kampungnet.com.sg/modules...view_album.php
The difference between this "kerbau" keris hilt and the 2 linked above is that the body of the hilt is fatter and more boxy. The 'batman ears' are actually the 4 fringes of the crown. They are present in all examples, just that they're not so pronounced in the other 2.
I have seen a hilt resembing this "kerbau" keris hilt a couple of years back, on a small Palembang keris. That hilt also had some motif carvings on the body, but not as profuse as this. I think the motifs on the hilt are merely embellishments added by the carver, and not really part of an established pattern.
I'm trying to find out where the "kerbau" keris originated from the Indonesian source. Hopefully he has some answers.
Battara - I think the selut is gilded silver. The highpoints are more silver than the recessed areas. The pattern is not typical Palembang pattern too. Typical Palembang patterns does not employ such big flowers.
A couple Palembang seluts I have. I have a 3rd selut, really beat up, but with similar patterns:
http://www.kampungnet.com.sg/modules...view_photo.php