I cannot tell from your pictures if the handles are gold colored ? It is possible that just the bale is 14K gold. If the handles do look like gold it usually is a paper thin sheet that is laid over the brass sides and held in place by folding the edges over the brass. However i do have one Wostenholm Gent's type knife in which the handles are gold, no underlying brass. I think these are rather rare. The more usual thin sheet of rolled gold has so little mass that it is not worth the time & effort to remove this thin sheet that might have $10 worth of gold.
As for value it is strictly supply & demand. Supply is large as this type of knife was very common 100 years ago and because of the gold people kept them, often never used. Demand is very low. Knife collectors are becoming more rare and the number who actually collect these type of knives is very small. Most on ebay end up selling at $20-$30. Every now & then you will see one listed for a few hundred dollars or sell at auction for over $100. This is because some people mistakenly think there is more that that amount of value in the gold. They are in for a surprise when the jeweller says "about $10 worth of gold at the most" as he hands it back to the forlorn buyer.