Mach Rider Credits
(Source 1: Vs. Mach Rider High Score Staff Initials)
HAL = Hal Laboratory
CSE = ???
HNY = Akio Hanyu
GSX = Hiroaki Suga
EGG = Reference to Eggerland I think (Japanese version of Lolo)
FLZ = Makoto Kanai
K.M = May be Makoto Kanai's name locally (Kanai Makoto)
NAV = Probably Yasunari Nishida
YOK = Possibly Miyo Aoki
MIK = I'm pretty sure it's Mikio Ikeda.
Hope this helps.
-Doommaster1994
(Reference 1: Mach Rider Toy)
The original toy came from the Creative Group and Toy Group which was affiliated to Gunpei Yokoi at the time. R&D1. R&D1 featured mach rider in their original WarioWare series again. Which links R&D1 as the production group most likely.