From Kisak's thread:
http://www.vikingsword.com/vb/showthread.php?t=9653
I think that the blade of the Katzbalger is a later addition as almost all original Katzbalger blades characteristically have short fullers at the forte. The pommel and quillons show Italian influence and are datable to the 1530's, the bone grip and brass band are replacements.
The hand and a half estoc is datable to ca. 1525-30, the pommel and quillons retaining much of their originally blued surface as well as their characteristic roped decoration; the two iron rings on the grip are later additions.
Tanks again, Kisak!
Michael