Just because a kit is available doesn't mean it is a copyrighted design. Most of the quilts in magazines are there to advertise the fabric from a specific company. In fact one magazine rep told me that one of their magazines is for that purpose only. Look at the design. Is it truly original or just a rearrangement of traditional designs. A copyright attorney told me you cant copyright three rectangles put together.
I looked through a couple dozen quilt magazines recently looking for a specific article. I was amazed at how unoriginal the quilts were. They were just to show off a specific fabric.