Other than blue MX, linear black MX switches and linear MY switches (higher actuation force) coexisted in G80 and G81 series with different prices. Someone correct me if I'm wrong, but this followed popular 1000, 1800 and 3000 series from, or near the start.
P.e, for the 1000 series launched in the late 80s, there was G80-1000 HCD (black MX), G80-1000 HFD (blue MX) and G81-1000 HBD (MY) for your "D" layout with "H" double-shots.