Thats a drum and nipple. That lock is not the extreme crap that Jukar first put out. But it still might not be all that good. Good news is that CVA sold guns with that lock shape for 25 years and Traditions still sells guns with locks that have similar parts. So lock parts should be available. In the early 1980's, a person could buy one of those locks new for around $10.00 a slightly better lock with a fly in the tumbler was $12.00. Right up until 10 years ago, CVA sold guns with the identical lock plate shape. (The bob cat rifles)
CVA sold that rifle as the Kentucky rifle. At first it came with a button rifled barrel. The rifling was so shallow that sometimes they looked like smoothbores. Later they had a pretty good quality cut rifles barrel. Dixie Gun Works still listed that rifle, in kit form, from CVA in it's 2004 catelogue for $175.00. Although I believe I remmember them being sold finished in the 1970's for $79.00 on sale. Early models had plain tumblers in the locks. By 1984 the CVA models had a tumbler with an adjustable sear engagement screw.