I have posted this same info on four other boards. Attached is a composite of the top right view of four separate AK mags, top to bottom:
Bulgarian, Hungarian, Romanian, East German
I personally purchased several of each of these mags and each was identified as to country of origin by a sticker label on the mag or on the poly bag packaging. Also, I paid attention to mags at shops and shows and to the ID that the mags had ("Made in "*****" stickers, for example). So trusting to the accuracy and veracity of the importers, I compared each of them to the other and drew some conclusions as to points of difference.
These points of differentiation are ID'd by green dots (not too professionally done, sorry) showing what IMO are points of ID, left to right in each view:
[img]http://www.armscenter.com/noah/akmagcomp2.jpg[/img]
Bulgarian: Rearmost sidewall rib ends in a 60 degree angle just under the reinforcing/feed lip plate. Wide and not sharply defined side ribs. Large circular spot welds visible on sides of front latch plate. This Bulgarian mag wears the textured "crinkle" paint finish.
Hungarian: Rearmost sidewall rib ends under the reinforcing/feed lip plate. Wide and not sharply defined side ribs. Small spot welds somewhat visible on sides of front latch plate. "02" Hungarian country code will sometimes be stamped on the left side of the "ridge" on the spine of the mag approximately 1/3 up from the bottom. (See bottom of this post for pic) Blued steel Hungarian 30s are seen, but they are usually heavily phosphate finished which is sometimes dry, sometimes oiled. Rough feeling to touch. The phos'ed ones soak up an incredible amount of oil. (These and the painted Bulgarians are my favorite steel mags-Noah)
Romanian: Rearmost rib ends before the reinforcing/feed lip plate, no angle. Wide and not sharply defined side ribs. Large rough spot welds clearly visible on sides of front latch plate. Dark blue almost black blueing.
East German: Rearmost rib ends under the reinforcing/feed lip plate. Visibly narrower side ribs are sharply defined. Spot welds are generally not visible to barely visible on sides of front latch plate. Some seemingly random letters will be found on the left side of the "ridge" on the spine of the mag approximately 1/2 up from the bottom. Medium to dark blue blueing.
The bottom view of the above composite is a comparison of the floor plates, L - R:
Romanian, Hungarian, Bulgarian, East German
Note the size, shape, and variation in degree of "sharp" definition of the stamped features of the floorplates. The "oval" on the EG is noticeable longer that that of the others, and again, the "sharpness" of the features on the Romanian, Hungarian, and Bulgarian floorplates is not as crisp as that of the EG. Also note the shape of the floorplate keeper tabs in the square floorplate holes; the Hungarian tab is light gray phos'ed and is almost flat compared to those of the others.
Finally, see below for typical "02" ComBlock country code on spine rib of blued Hungarian mag.
[img]http://www.armscenter.com/noah/02mag1.jpg[/img]
It is usually 1/3 up from the bottom on the one side. Many ComBloc countries did not mark their mags because of sales to client nations and revolutionary organizations in which case ID to the supplying country was not desired.
HTH,
Noah