Hello Sid,
Apologies for joining the party late!
Despite handling this keris a long time ago, I can't add much to what has already been mentioned:
I'm pretty sure the gonjo got crafted on Bali or Lombok.
The pamor does resemble what can be, for example, commonly be found on keris from Madura; however, as already mentioned for the rougher surface texture, this doesn't negate a possible origin from Bali/Lombok, either!
Once you receive this keris, a peek on the pesi might allow additional insights!
This keris was exhibited & published a while ago: Follow the link given by me in post #31 of this thread:
http://www.vikingsword.com/vb/showthread.php?t=21646
Check piece #16 on page 90 of the catalog in English language!
This catalog is also still available as book in both languages, I believe.
Regards,
Kai