Yep, the hilt does look like bat. My initial thoughts were more based on the seemingly feathered wings and the legs. I don't think the legs are human at all. Human legs don't bend forward at the knee like a bat's, or eagle's, for that matter.
The other thing is, Garuda is sometimes not depicted with a bird's face, like these couple of images I found online of Garuda carvings in temples. There's also a Balinese hilt in the small red book "The invincible kris" which depicts garuda with a 'snout' rather than a full beak.
But, I also found a bat image which looks physiologically very similar to the hilt shown here, down to the 'knob'
The hairdo is funny, or could it be a crown? Or this hilt could be one of the fancier forms carved in Bali during its post WWII "Renaissance" where new forms of old icons emerge. I had Balinese hilt depiciting Garuda which looked like Heckle and Jeckle.
