THERE ARE SEVERAL THINGS THAT INDICATE AGE.
1. MATERIALS/FITTINGS. ALUMINUM INDICATES LIKELY JUST BEFORE TO AFTER WW2, (THE BLADE CAN BE OLDER AND REMOUNTED)
2. THICKNESS OF THE BLADE AND SIGNS OF FORGEING ( WATERED STEEL) CAN INDICATE AN OLDER BLADE. MORE RECENT ONES ARE OFTEN MONO-STEEL AND NOT SO THICK. TRUCK AND JEEP SPRINGS WERE VERY POPULAR FOR RAW MATERIAL AROUND WW2
3. PATINA , STEEL IS EASIER TO FAKE AGE PATINA THAN WOOD OR LEATHER.
4. GOOD NATURAL WEAR FROM LONG USE,(NOT ESPECIALLY GOOD FOR DETERMINING AGE BUT A GOOD INDICATION OF AUTHENTIC LOCAL USE.)
5. IN SOME CASES SIZE CAN BE AN INDICATOR OF AGE. SOMETIMES SMALLER IS OLDER AND SOMETIMES THE OTHER WAY AROUND.
ITS COMPLICATED AND ESPECIALLY DIFFICULT TO DETERMINE AGE WITHOUT GOOD PROVENANCE AND ONLY PICTURES TO GO ON.
I THINK THE TOP ONE LOOKS TO BE A OLDER PRE WW2 ONE BUT AM JUST GUESSING.