That's similar to the impression I was getting. G87 seems to be a very specific set of health industry products that gained their own series number.
Then you have the Strait (for example) with no Gxx number at all, when it should presumably be G85 (scissor).
Would be interesting to see how G86 compares to Topre in feel. Someone mentioned recently at DT that Topre domes can be tuned for feel as they don't have to serve physical actuation purposes. I've had a couple of Dell rubber sheet keyboards apart while still connected, and with the rubber sheet removed, it's like typing on a touchscreen. The amount of force required to flex the top dome sheet by the ca. 0.07 mm gap is negligible, or so it seemed to me. You can't "feel the membrane" as I've seen mentioned before.
(Random tidbit: membrane sheets are the same thickness as a typical sheet of paper.)