I have. Given timing, I was only able to use it on my finish kit order. I'll have to check back and see if they honor it for a FWF kit but my recollection was that it was limited to the 4 main kits (emp, wing, fuse, finish) of any aircraft.
Check that out if you haven't already. I emailed credentials to them. A little back and forth emails and they approved our status and said the discount will be applied to the finish kit I had just ordered.