Hi Fernando,
I hope you don't mind me adding this, but this recently finished on eBay. I did bid ....but was not confident enough to bid too much....and (possibly) missed out on a bargain ?
I am not certain that this would be regarded as a Navaja as it is similar to knives described as 'Roman folders'. Whichever it is ...it is large. Blade approx. 25cms Opened approx. 53 cms
Any ideas
http://cgi.ebay.co.uk/antique-foldin...QQcmdZViewItem
Freebooter, I am no expert, but you have some really nice examples