Here my 1957-ish Junior that I modified 40 years ago ( What! 40 years ago??? Shit I'm getting old ). It had already been chisled for a humbucker and refinished once, so there's no guilt for trashing an all-original Junior. I routed it it for a neck pup, switch and controls, and slapped a dozen or so coats of lacquer on it. This was my only Les Paul up until about 20 years ago when the hoarding began... Regarding the original question, sure a humbucker works in a Junior! I'd say that this guitar sounds a little darker than a maple-capped LP, but it's still a rocker.