I don't think the second hilt (very nice carving indeed!) is Rhino, to me looks like this may be some form of albino water buffalo (which is my favourite material I have a few in very different shades of colour )
From reading about rhino hilt, often that looks like " wood" to many observers. It tends to be mat and not shiny.
I will quote you some threads where you can see examples of people asking questions such as yours
http://www.vikingsword.com/vb/showthread.php?t=21327
http://www.vikingsword.com/vb/showthread.php?t=28853
This hilt you show...I think there is a strong possibility that this too *as another one that you have shown before) is not a Kris hilt but a Betel nut chisel