It may be a prestigious honor, but this year’s recipient of the Louis P. and Evelyn Smith First Amendment Award did not accept it with furrowed brow. Jim Downey has spent three decades mocking the serious stuff as a writer on ‘‘Saturday Night Live.’’ Appearing with his longtime friend, former ‘‘SNL’’ cast member Bill Murray, Downey told a packed house at the Ford Hall Forum at Suffolk University Tuesday night that ‘‘nothing should be off-limits to comedy as subject matter ... I sort of like to grab live wires and see what happens.’’ He went on to show a few clips related to 9/11 that demonstrated that approach. While Downey was the honoree, Murray was the star, interjecting several times with deadpan quips. (‘‘Some of you aren’t old enough to have illegitimate children,’’ he said, referring to his own blended family.) Murray, 61, fondly recalled his former ‘‘SNL’’ castmates, but said Downey, with whom he started in 1976, and ‘‘Danny’’ [Aykroyd] are probably his only true friends from the show. A former president of the Harvard Lampoon, Downey seemed puzzled as to why he was receiving the award, which may explain his funny but unfocused talk. Downey and Murray admitted that rather than plan their presentation, they listened to music (Emmylou Harris) on the drive from New York City. The pair took a few questions from the audience, with Murray occasionally reaching into a shopping bag and tossing candy into the crowd.