I have an FAQ on E German field gear here: www.akforum.net Go to the "field gear and equipment" forum and the thread is tacked at the top.
First thing, describe the pouch and the web belt. My guess is you have one of the various "randrop pattern" 4 cell AK mag pouches and the green web belt. The pouch definitely fits on the gray web belt with the sheetmetal buckle with the E German logo on it, but might be too thick.
The green web belt is from when the E Germans redesigned their web gear in ca 1987. Pouches will have wire metal hooks similar to old british field gear or the old US M1 Garand cartirdge belt.
Is this making any sense so far? Post some pics (or steal them from sportsmans guide/provide a link) and i can help you out more
[ETA] the three pack...has to be the green web belts, as the gray ones come in a four pack (don't ask me how I know that).