You probably didn't mention it's size, insert colors, inlay shape, etc. No need to, all this is easily seen in the photo of the chip. Same as whether the chip was a backup chip or not.

I think 18 monthes is long enough, but I think your statement above is not really fair. Whether a chip is a backup chip or not is not something which is facially apparent such as color, inserts, etc. It takes knowledge beyond the image to know that the chip was a backup. Your argument would justify selling a Fantasy Chip without disclosure since one could look at the picture and see it.