Hello!
Almost a month ago, rocco_16v posted on
deskthority something that gave us very concrete IBM-written evidence for the existence of "Keyboard G"/"Model G" - presumed to be what Model Ms should've been - outside some inner assembly rear labels found on IBM U.K. made keyboards in the mid-'80s. Seeing that gave me the itch to dive deeper and write about it, and what I found was very interesting. "Model G" lived on after that 1985 internal IBM communiqué; no longer a major family designation like Model F or Model M, but more narrowly defined and repurposed. Models 1A (122-key Model M Converged Keyboard) and 1B (104-key Micro Switch ST Quiet Touch Keyboard) were introduced as G's counterparts. The evidence for G, 1A and 1B had been sitting under my nose for ages...
https://sharktastica.co.uk/articles/model_gTLDR (as per my understanding)- Keyboard/Model G was intended to be the Keyboard/Model F successor that at some point became Keyboard/Model M. As very early Enhanced Keyboards have "Model M" on the back, this must've happened very early on and likely just before general availability.
- Model G was relegated to designating the IBM Enhanced Keyboard under the Model M umbrella, unlike how "F" and "M" were applied to many keyboards.
- To complement this "new" G, Models 1A and 1B became counterparts and in the case of the latter even transcended the Model M family. This new nomenclature survived into the 2000s via IBM i documentation.
As always, I won't draw an absolute line under these conclusions. I still have questions to answer and will make updates if needed. Any further input or comments are appreciated.

Thanks for reading!