I'd say that your smaller knife was made in the 1940's .... many of this type were sold/traded to U.S. servicemen in Europe for a pack of cigs (according to my dad , who brought back 4 of them) , esp. after the 2nd World War ended .
They were more commonly made with antler (horn) handles .... can't really tell if yours is , but I'll take your word that it's made from bone .
Aluminum was the most common mat'l for the butt of these type of knives (some were made from antimony alloys too) , with a slotted brass nut that tightens the leather/horn/bone/brass handle assembly to the knife blade , which has a threaded tang at it's end .
Generally speaking , many knife collectors will look for items that are in pristine condition as a "upper limit" guide for pricing 'tip-top' knives (just like collectors of many things) , with values declining @ a 'per defect' basis that an item has .
Many folks who are 'home based' sellers will check Ebay & sim. websites to get a feel for what folks out there are willing to pay for such items , just as you have ....
Some knife shows will garner better prices than the next one , and negotiation is sometimes the key to the happiest buyers & sellers .
These little knives are/were very functional & solid , but have no great value to collectors that I know , except for the ones that are 'like brand new' .
Cool little knife that brought back memories , bob535 !