If John "Junior" Gotti hung up his gangster hat as he claims, it's news to mob turncoat Frank "Frankie Fapp" Fappiano — but then so is a lot of well-known mob lore.

"Did you ever hear that he withdrew from the family?" Assistant U.S. Attorney Joon Kim asked Fappiano yesterday, referring to Junior.

"No," the mobster-turned-rat replied during his third day of testimony at Gotti's racketeering trial.

Under questioning by defense lawyer Jeffrey Lichtman, Fappiano admitted he hadn't seen or spoken to Gotti since 1996, but quickly added, "I'm sure I would have gotten word that he retired. That would have been something important."

The witness went on to say he has missed other key Gambino family events, such as the sweetheart deal notorious turncoat Salvatore "Sammy Bull" Gravano got from the feds after putting John "Dapper Don" Gotti away for life.

"You never heard that Sammy Gravano got sentenced to five years in prison for 19 murders?" Lichtman asked incredulously.

"No, I never heard that," Fappiano replied.

He also didn't read Gravano's book, "Underboss."

"I don't get off on reading mob books," Fappiano said, adding that he'd "skimmed the book" and "looked at the pictures," including one of himself. "I am in the life. I didn't need to read it."

The most embarrassing moment for Fappiano came when Lichtman confronted him about highly publicized allegations that he sent love letters to one of the lawyers on his case and was caught holding her hand during a prison visit.

"I wasn't holding hands with her. She took a pen from my hand. The [correction officer] took it the wrong way," Fappiano stammered.

Asked about "steamy" letters between them, the red-faced turncoat said, "I don't know if they were steamy. She did have some letters. They were pertaining to my case — it was very embarrassing."