kbt check out the two pairs of rouletted stamps being offered. note the spacing and shape of the separations. blow them up if you need to then look/compare them with the singles. experience and examination of real items is required in this area. the roulette gauge was such that by removing every other perf they could be faked.
Thanks m and m, I think I see it now. I put the enlarged images of the single next to the pairs and there are some differences. What I picked up is the "nubs" at the top seem too narrow, and some of the ones on the left side have curve/sloped sides instead of straight.?