EOD - I was going by information I got from what was the East German Crime lab of the non-production locally of certain items. The 7.9 x 57 blanks, for example, were likely loaded outside of the DDR. Cases can be from the DDR but also Czech. The same for short range 7.62 x 54R. Of course, despite the ammo requirements for it in the early days of rearmament of the DDR, a DDR-made cartridge case in 7.62 x 54R is a rare bird. I still have my DDR cartridge collection, and I never was able to obtain even an empty 04 7.62 x 54R (or o5 for that matter, if they ever even made one). All my DDR 7.62 x 54R rounds, other than Stahlpatronen (gauges) were loaded in non-German cases.
Regarding 04 and 05 not making clips, I have no doubt you are correct about that. That’s why I put the caveat in my reply about “…or any other marking that I could identify as being from the DDR.”
I knew that most of the Warsaw Pact light aircraft were made in Czechoslovakia, as were a lot of the tanks. Probably other things as well.
The handguns used early on in the DDR were a hodge-podge of pre-1946 German and other European pistols. When it was decided to go to the 9 x 18 mm Makarov, the first used in the DDR were Russian and probably were the primary reason for the letter-coded dates on Russian Makarovs made from mid-1955 until mid-1960. Then, the Germans started making there own, with a tiny amount made in 1958, a relatively small amount in 1959, and then full-scale production from 1960 until 1965, when they stopped making it. After that, they purchase PMs from Russia and Bulgaria, and Feg pistols from Hungary and some Carpati pistols from Romania. They also used PSM and Stechkin pistols from Russia, Skorpions from Czech Republic. I had a DDR holster for the Skorpion, and still have one for the Feg PA-63.
Well, an interesting subject, and surprising is how little we really know about East German production considering it is all within our lifetimes.
It took me several years, corresponding with people whom one would think would know, to find out the original name of the specific Ernst Thalmann factory that made the DDR PMs (Simson & Co. Suhl), and I found that out first from a Czech! Of course, with all the digging by collectors, we know a lot more now than we did even just ten years ago.