According to this article, Maharis and Buz Murdock actually had quite a bit in common. Maharis wasn't from Hell's Kitchen, but "his family still lives in Astoria, Queens, a lower middle-class neighborhood." Like Buz, Maharis was a complex mixture of sensitive and tough. He loved singing, but he also wasn't afraid to go kick someone's ass when the occasion called for it. A highlight from the article: "He is actually quite similar to the character he plays, and writer Stirling Silliphant and producer Bert Leonard had him in mind when they created the show."
To demonstrate that he was the genuine article, Maharis showed Scheuer one of his war wounds. "See this scar on my knuckles. I got that when I hit a guy with buckteeth with an uppercut during a street brawl. But that scar taught me something. When your opponent has buckteeth, use a hook not an uppercut."
You don't mess with Buz Murdock. And you sure as hell don't mess with George Maharis.