Who owns the quilt after the shop has displayed it? That might be the deciding factor. If they contribute the materials (they are doing so "at cost", remember)and get to display the sample as long as they need to, then perhaps the quilt could be yours at the end, IF that appeals to you.
This is the dilemma every shop faces, how to handle the samples. It's why, in my former shop, I hired a sample maker. She came in a couple days a week, worked for the same (sorry!) wage the others did, and we used shop fabric, materials, my on-site studio and machine, and owned the sample afterward, which I occasionally sold later.
Before I bought the shop, samples were often made by the staff, at home, with shop fabric, (plus more fabric than they needed), and they were keeping the samples as well as being paid. Not a good business arrangement as far as I was concerned.
Talk it all out beforehand to avoid ANY problems later, can't stress this enough!
Jan in VA