Yes, the bowl on eBay is indeed by Johan Wilhelm Johansson, father of the much more famous Willy Johansson. JWJ was Hadeland’s master glass blower and the craftsman in charge of the workshop that developed and made the art glass range from around 1950. He also designed some 40 models which he executed himself. Also, quite a few of the other Hadeland designers’ art glass pieces you find from the 1950s, including those of his son Willy, were executed by Johan Wilhelm. On the earliest pieces you can find his initials together with the designer’s own. I know this can be a bit confusing, but it was Hadeland’s way of acknowleding both the designer and the craftsman behind each piece. Johan Wilmhelm Johansson retired in 1958, but a few of his models bearing his signature remained in the catalogue for some years, including your eBay bowl.