yeah, i remember in years past some of us expressing angst over these near worthless gauges; i've had a couple. i would not know where to begin looking for those old threads... the drive is i "think" similar (not sure the same) to K4-5 era. and i am certain your observation is correct, cost effective, cost containing as cheaper, more efficient ways were discovered to mfg'r parts made up complex sub-assemblies. kind of interesting a gauge like that; decades earlier the engineering, manufacturing technology, and machines required to produce a gauge like that did not exist. that gauge is a product of human and engineering evolution, one moment at a time over the span of millenniums.