If you still have the plans and parts I'd say it IS a kit - made by you.
And It looks gorgeous! :Bravo:
Like Zathros said, it is not "just" a model, it crosses the border to art. Admittedly, every designer is an artist and we have many artists here, but your way of construction is pretty unique. I haven't seen it before.
At first I thought the car was larger than it really is. Your designing procedure can be used as a template to make a much larger version, maybe out of plywood, as a display piece for the garden, for example. And with a few small changes you could add opening doors and an interior with a turning steering wheel for the kids. I can imagine that would be quite a hit.