I get that Bone Wolverine can be decapitated. And I get that the Highlander has spent hundreds of years mastering the art of decapitation through swordplay.
But I don't see Wolverine going down to that ... it's very hard to credibly pit a T.V / Movie fictional character against a comic book one as 9/10 the comic character just has far, far better feats. Bone Wolverine has dropped dozens upon dozens of blade wielding ninjas at once for instance ... I mean, has Highlander ever taken on even just a dozen skilled foes at once?
Bone Wolverine carves Macleod up with ease IMHO. Duncan has the skill to take a few perhaps, but not a majority.
Duncan Macloud has taken on dozens of armed foes, many many times. Both in his comic appearances and in the show. Furthermore, each time he killed an immortal he grew better all around stat wise. He earned the dead immortal's skills and memories, his attributes improved as did his abilities. By the end of the series before it became crap, he had over 600 immortals to his name including immortals that were far above wolverine in physical attributes (including Kronos the strongest immortal ever seen in the show). If Duncan is in his final episode iteration he could easily defeat wolverine being more skilled then him and better physically. Don't let the crappy special effects of the show fool you. Duncan was a beast by the end of the series.