Bill,
That's a lovely maduran keris. Worth cleaning and staining.
The ukiran is the cuirassier type. Very well carved. The crack is a pitty.
http://blade.japet.com/KRISS/K-Ukiran/U-madura.htm
The wrangka is very nice carved as well. The pendok has the typical maduran european influence like the lower piece of the scabbard of a sabre.
Maybe a newer keris but in my opinion a very nice one.
Wouldn´t think about changing the ukiran.