Opinions On This W3 War Savings Stamp In Certificate Booklet

I posted this earlier but I could not get a good picture of it. Finally had a better picture taken so I am reposting it for your opinions. I believe this is a W3, but since I have never seen one in person, that is just my opinion. Measured from the first full perforation from the upper right corner. I count 8 little stubs in 20mm (although it is difficult to be precise because how ragged and irregular it is torn). I believe this is consistent with what a W3 is supposed to be perforated and certainly far less that a W2 would be.

I would really appreciate you opinions on whether I made a good purchase or not. Thanks in advance for looking and taking the time to respond.

Yes, this is a W3. It is considered used since it's been mounted to a certificate (these were mostly not cancelled, and any savings stamp with no gum is used).

Looks like "line Rouletted" to me.

Yes, seller advertised it as used and I would consider that to be fair grading. I am happy to have one because the price of mint W3s are beyond my reach. Being in a certificate makes it hard to display, though.