Cool info. And pics! Few notes:
To my knowledge AK was adopted in 49, not in 48.
Until it became AKM the gun’s official abbreviation was AK, not AK-47. When the receiver was switched from stamped to milled the official name became “Oblegchyonnyj (Lightened) 7.62mm avtomat Kalashnikova (AK)”.
Official abbreviation of the latest 74 is AK-74M. It makes sense if you think about it. My hunch is that calling it AKM-74 would be a bit confusing. It is for the same reason the gun was not called AKM-74 initially even though it was based on AKM, not on AK. There can only be one AKM
And a bit off-topic:
The gun was originally adopted without bayo. Bayonet appeared first with the Type 2 receiver and was redesigned for AKM. AKM bayonet was patterned after the diving knife designed for the Soviet navy scouts by Lt.Colonel Todorov(?).
At different development stages the gun had features some people can’t imagine life without: thumb safety, bolt hold open device, gas regulator, aluminum magazines and even a telescoping monopod that was stowed in a front pistol grip. All, obviously, deleted.