AK-D

"“What you have there is the Terran classic, the AK-47. These have been in use for over a thousand years and there is a reason. Your [ Z’uush ] physiology is close enough to ours [ Human ] that you should be able to use them with no modification.  Thirty round magazine, reliable, completely chemically powered, and will tear right through a personal deflector.  They won’t show up on sensors at least at first.  We also have armor piercing rounds specially designed for standard combat armor.  Right through the screen then right through the vest.” Johnny, Army Surplus"

The standard weapon of the Terran Republic. Most likely based on the Avtomat Kalashnikova. The Rifles sold by Johnny to T’sunk’al where Refereed to as Ak-47.

Mark Twelve
The Ammo bought in Chapter 1:Army Surplus, was identified as at least Mark 12 Armor-Piecing ammunition by Jon Wintersmith in 2. Chapter Damage Control

Mark Fifteen
Sold by Sheila Donovan in 3.Chapter: Precious Cargo.

Army Surplus
The "AK-47" sold in this Chapter where of an older Model with a wooden stock, since polymers where running low at the time of their construction.

The Name AK-47
The Rifles sold by Johnny to T’sunk’al where Refereed to as Ak-47. Most likely as a Marketing/one catch all term. The Ak-47 was replaced by the AKM in 1959. The story starts almost a Millennium later.

The Rifles sold by Sheila Donovan in Chapter 3: Precious Cargo where just referred to as AK's.

The Basis of the AK-D
All AK's with the exception of the AK-47 Type 2 and 3 where stamped metal. This means they where (for the time) easier and faster to produce. There are some theories that the milled receiver of the Type 2 and 3 are better in recoil control, due to their higher weight, than the stamped receiver of e.g. the AKM.

Since the Terran AK-D are constructed in molecular forges, the time saving of stamping no longer applies, so there is no reason for the AK-D not to be based on the AK-47 Type 3, with all the quality of life improvements since then.... Well.... If you exclude the fact that you could carry the difference in weight in ammo....