I had a LK-93, which I believe was the American-Made replacement, IIRC. I think I bought mine in 93 or 94.
Did you get a breech plug wrench? If not, you will need one, or you can make something to remove the breech plug and nipple. The rod does look short. All three of the Knights I have owed had a threaded insert on each end of the rod.
Now the good news. Knight is located in Athens, TN, and their customer service is fantastic. Just contact them and they may be able to tell you a little more about that model and may have the parts you need. My Disc Extreme came with the wrong breech plug. I had been working with one of the techs, and mentioned that I would be in the area on business, so he suggested that I bring it by. The tech met me in the lobby with the correct breech plug, a hat, and a little goody bag.
As far as using it, my LK-93 shot best with 90gr of loose Pyrodex, and a 245gr .45 in a sabot, using a #11 cap.
I never tried the pellets in LK-93, but that is all I use in my Disc Extreme.