There's also the Danger Room fight with Wolverine in #273. Gambit wins it, but the circumstances matter.
Logan is still recovering and knows he's lost a step. During the exercise, a Lady Deathstrike simulation distracts him, and Gambit takes the opening with his staff. That's the fight. It isn't proof that he could casually beat Wolverine under any circumstances.
It does show that he'll use an opportunity when one is there. He's not going to politely wait for his opponent to get comfortable again.
By the Shi'ar adventure in #275–277, he's fighting alongside the team against a situation involving impostors and powers copied from people they know. He's still a newcomer, but he's already been through a lot with them in a short stretch of issues.
There's still plenty about his earlier life that the team doesn't know. They have a thief who helped Storm and ended up staying, and they're getting to know him while he's fighting alongside them.
There's also the Danger Room fight with Wolverine in #273. Gambit wins it, but the circumstances matter.
· Comics / Marvel / X-Men