44RM - nice boxes! I’ve collected 9mm para boxes for 35 years and only have a poor specimen of the Geco, and never have found one of the RWS, although I have seen them.
However, where did you get the information, which you allude to, that the original bullet wieight of 9mm Parabellum was 100 grains? I have a 9mm cartridge with 8 gram (124 grain) tuncated FMJ bullet, with headstamp * D.M. * K. These are pretty-well acknowledged to be the first production-run 9mm para rounds, predating the “K DWM K 480C” headstamp. They date from approximately 1902. The original bullet weight was 124 grains, and that weight, or 115 grain, accounted for much of the world-wide production of this caliber until about the 1960’s, when expecially in the U.S., they started playing with bullet weights from as low as 85-90 grains to as high as 147 grain in relatively normal loads, and higher weights for silencers. For specialized Silencer work, The British and Germans, and perhaps others loaded bullets heavier than 124 grain earlier than that, but again, for regular production, 115 and 124 grain were the norm.
During WWII, to save strategic materials, iron cores and singered-iron bullets were used, and these resulted in bullet weights lower than 115 grains - around the 100 grain mark - but this was not the norm except in the WWII years, and their use was probably much more wide spread in Machine Pistols than in either the P-08 or the P-38 Pistols, although certainly they would have been used in those weapons also if it was all that was available.