Why on earth would you modify a test paint or grab bag? I did see once on ebay where someone was selling a grab bag that had a small altered spot that was fully disclosed with before and after pictures, which I am glad they did disclose it
I really really want an Atlantis piece, a while back a fledgling came up for sale at a reasonable price and I wasn’t able to try and get it at that time, hopefully one day I can get one