Reputed mobster Enrico Ponzo will present two faces to a federal jury beginning next week — clean-shaven then full-bearded — ­if prosecutors have their way.

The feds first want witnesses to recognize the accused hit man from his “prominent cleft chin,” then with a beard, mirroring his appearance while on the lam in Idaho.

Prosecutors say the reputed gangster infamously tried to whack former Boston Mafia godfather “Cadillac Frank” Salemme at a Route 1 IHOP in 1989 as part of a failed coup of the Patriarca family. Ponzo then allegedly fled the state in 1994.

“It could be extremely difficult for witnesses who knew Ponzo only before he became a fugitive to recognize Ponzo without seeing his noticeably cleft chin,” prosecutors argue in court documents.

Gerard T. Leone, a former federal prosecutor who served as Middlesex district attorney for six years, said the facial hair flip-flop is slightly unusual, but “not unreasonable.”

“If the defendant has a three-inch afro and the witness says the man was clean-shaven with a bald head, the jury says, ‘That’s not who I see in front of me,’ ” Leone said. “It’s within the judge’s discretion to allow adjustments to appearance.”

Ponzo, 45, shouldn’t grow accustomed to his new look if Judge Nathaniel M. Gorton goes along with the request. As the trial progresses, prosecutors want Ponzo ordered to regrow his beard for the benefit of those witnesses who knew him as cattle rancher “Jeffrey John Shaw” at the time of his 2011 capture in Marsing, Idaho.

Defense attorney John Cunha Jr. said he will oppose the motion, calling it “hilarious.” The stubble standoff will likely be debated at tomorrow’s final pretrial conference before Monday’s trial opens.

Former federal prosecutor Brad Bailey said a request like this “doesn’t happen a lot, but does happen.” Bailey said the allegation that Ponzo was a fugitive from justice living under an assumed name “gives the motion solid traction.”

Prosecutors concede the federal First Circuit Court of Appeals for New England has never had to rule whether a defendant can be forced to shave for trial, but similar orders were upheld in federal robbery cases in California and New Mexico, where suspects clean-shaven when the crimes occurred showed up in court with woolly faces. Both were convicted.

Swampscott native Ponzo has pleaded not guilty to an 18-count indictment charging him with attempted murder, racketeering, witness tampering, money laundering, extortion, drug and weapons possession, and unlawful flight from prosecution. Authorities claim they recovered $167,000 in cash and gold from his farm along with 33 guns and 34,000 rounds of ammo.