Peened bottom portion of the “knucks” (or properly "knuckles" as already pointed out) looks exactly as it should (perfectly circular peen). Scabbard looks awesome too, as is the set is definitely worth a solid $500.00.
According to Frank Trzaska’a website @ http://www.usmilitaryknives.com/amewm_18.htm The flanged models of triangularly bladed wooden handled knuckle knives are properly designated as the M1917s and the L.F.& C. pyramid knuckled ones (as you have posted) are properly designated as the M1918s. The bronze/brass handled ones are designated M1918 MK.Is. The reason is they are,
“Designated as such in Benedict Crowell’s America's Munitions we have continued to use the designation. There is still much controversy as to which is the Model 1917 and which is the Model 1918 so we will stick with the Assistant Secretary of War until proven otherwise.” (Trzaska,1994).
The date confusion seems to be a contemporary issue between the contracted companies and the US War Department. Some contractors thought they were putting the year of manufacture on their knives while the War Department was expecting to see a model’s designation (this confusion happened with some M1917 bayonets receiving “1918” dates as well). In 1917 defense contracts for rapid mobilization were awarded without the pedantics of the normal (slower) acquisition system's detailed/specified contracts. Obviously, the knives with mixed up date/model designations were otherwise serviceable and the AEF were desperate for them. So we collectors have been stuck with the confusion over dates versus models’ designations ever since. This has all been discussed before on the forum by wiser men here http://www.usmilitariaforum.com/forums/index.php?/topic/65710-wrong-year-buddy-model-1917-vs-model-1918-trench-knife-nomenclature/ I apologize for the long winded response, but it’s one of those “chicken versus egg” questions, which does not lend itself to a short answer.
Trzaska, F. (1994). AMEWM 18. Retrieved January 6, 2014 from http://www.usmilitaryknives.com/amewm