To me the blade doesn't look like it has been forged just before being picked up. I believe the workmanship on the prabot details is average at most for Balinese standards - it's a nice blade though! (I yet have to come across a genuine keris Bali blade which I don't like...
)
My best guess would be first half of the 20th century (19th c. seems also possible). I'd be interested to hear wether this piece shows any details which would specifically indicate 19th c. or otherwise.
Anyway, congrats Daniel - that's a really nice start for a keris collection!
Regards,
Kai