Fillers like this do in fact usually go for below 1% of catalog, and the only reason it's sellable at all is because it's so expensive sound.
At a data point, I would point out that the Scott catalog value for this stamp (2015) used and sound is $1,000. The catalog value used and cut to shape (but otherwise sound) is only $10. 1% of catalog value when it's just cut to shape (with no other flaws). Scott doesn't price the unused stamp cut to shape, but that gives you an idea where you're starting: 1% of CV cut to shape, with other faults it should sell for even less than that.
If the stamp looked good facially it might be another thing, but this is a pure space filler and I'd rather see the empty space than a severely mutilated copy.
Cut to shape is generally how these were used and collected. If its used and cut to shape, its probably genuine.
If its cut square, beware, especially if all 4 flats are intact. Make sure its got a watermark. The way these were printed, the gap in between stamps was tiny, or non existent. Many were printed overlapping.
Dynamode the stamp you show has impossibly large margins to be a stamp rather than stationary.i have some of the embossed issues, but I couldn't afford the price of four margin specimens, I have settled for presentable lightly cancelled 2 and 3 margins. I hardly dare look for watermarks. having read rog dcams post about cutout postal stationery.
Noocassel. The stamp I showed with huge margins, read what I wrote above the picture. I clearly stated that is a postal stationary cutout. The issued stamps cannot have margins that large, as they were printed too close together. We also know its stationary because it has no watermark.
There are other similar types, but they are easy to spot, as they have numbers in circles showing the dates of issue. These really are one of the easiest issues to identify between stationary and issued stamps. Even for me.
Rogdcam is correct. But failed to see the picture, or read what I said, in the 1st post showing the watermark on my unused stamp.
I realise this thread is not very current, but I bought a 6d dull lilac not cut to shape with 2 margins complete for 100 pounds plus12% hammer price at an auctionon Tuesday. Thanks to Dynamodes postings I knew to look for the watermark and it is present.