Jonnynonos:
The notion of a professional hitman is one of those stereotypes that stubbornly refuses to go away. There may be some rare exceptions,but in the OC world the job of hitman doesn't exist. No made guy or wanabee associate is going to be paid for doing "work" for the Family. If you get the order,you do the job,end of story.
Kuklinsky not only was full of more s**t than a Xmas turkey,but he was only photographed at the Gemini Lounge once,and may have never even met DeMeo. He sure as hell didn't do any hits for the Gemini crew. There would be no reason for Roy to ever go outside of his army of psychos to have a guy killed.
Bottom line,the idea of someone being paid on a regular basis for doing nothing but killing,is a cinematic fantasy.