The 2 digit model numbering was for the original piston stuff. The three digit and the associated model sequencing came with the turbine helicopters. That's why someone had the idea of starting the MAPL line with "3" as the "third generation" (first being the 47 et al, second being the 204, 206 and the derrivatives, ignore 222 and derrivatives as being a generation on its own, and that makes MAPL third.)
Bill Stromberg was the father of the "Global Ranger" name. Mike Redenbaugh wanted a real name for the 429 and not just a number. You had "Jet Ranger" and "Long Ranger" as Bell's named civil models, "Twin Ranger" had already been used by an STC. So given the international participation in the pogram, Bill suggested "Global Ranger."
I don't think that name has really stuck though...