I agree with being original. I am sure if you are going to make them for your personal use, then copying a premade lure would not get you sued. Copying a lure is good to get a feel for the process of mold making by working with as few variables as possible.
Personnally I sculpt my own designs and use my own color combinations based on minnows and crayfish from the areas I fish. I think showing the fish something original is always a plus. I have recently landed by personal best bass on a design I came up with recently.
In the end though, just doing it yourself and catching something on it is the best part.