After a long wait, the pieces I purchased at the San Giorgia auction arrived. The auction photos and original thread is here:
http://www.vikingsword.com/vb/showthread.php?t=22641
The auctioneers are based in Genoa and they feature a book titled "Il Costello Genovese". I got a copy of the book in the hope that it might include knives similar to the ones I bought. It did not, so I would assume that the three knives that appear to be Italian are not from Genoa.
As Fernado pointed out in the original thread, based on a figure in "Armi Bianche dal Mediebo all'Eta Moderna", this one with the hooked grip is probably from Sicily.