Far left is a '74. The other 2 are AKM. AKM has the vent holes. Middle appears to be Tula, the other two Izzy. You will also find the spring on late model AKM.
Thanks so much for all this info. Looking forward to getting some time tonight to look at what I have and compare it to the info you have provided.Here is my meaning of "pocket". As you can see, there are examples of parts where both the retention spring and the rectangular relief / pocket are present. You can see that the small metal insert is no longer part of the design at this point. The insert used to be present on AK47 and early AKM parts. This would signify that the piece im showing here is a mid production IZZY AKM part, as the palmswells are squared, the color range of the varnish, and I think there was a diamond proof /acceptance mark somewhere on here where Tula ones are circular, sometimes with "H" or "K" in them. I've also seen ones where it's just an "H"
When it comes to markings, I've seen that they are so numerous considering the ones documented on this forum, and ones that I've seen on my personal collection that have never shown up on this forum that it seems too arduous or impossible to catalog every one ever made let alone know their precise meaning, but it is generally understood that the diamond marks are acceptance marks regardless of the lettering or numbering inside.
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