I do not know what the rings on the bullet signify - they may only be a factory “in-house” ID or something that was specified in the contract so that bullets from various contracts could be identified from each other. I just don’t know.
However, your CIS (Chartered Industries Singapore) and FN (Fabrique Nationale Herstal) cartridges are not proof loads, but rather ordinary ball Mark 2Z rounds. A huge amount of this ammunition - both makers - came into the United States from Singapore or Malaya, not sure which, some years ago. We sold it in our store. I still have 3 or 4 full boxes of the CIS Ammo (packed in 12 round boxes, labeled only “Revolver, 0.380 2Z, 12 Rounds, CIS”) that I kept for my trade dupes when I sold off my own Webeley .380 Revolver.
The GC on the headstamp of the CIS round is a date code which I believe represents “73” (1973). I think the code is just straight alphabetical, ie: A=1, B=2, C=3, etc.
I can’t say for certainty about your DC (Dominion Cartridge, Canada) load. I am used to seeing these rounds with a purple primer seal, not a red one, although admittedly, I have not seen one so late as 1956. I don’t collect this caliber, but used to shoot it. I suspect, though, that it is just ball. Most Canadian handgun-caliber proofs I have seen - 9mm Para normally - have either copper-washed cases or nickeled cases (well, not sure they are nickled, but silver in color anyway - there is other plating besides nickel). I would doubt in this caliber that they are tracers, the normal meaning of a red primer annulus on Commonwealth cartridges. Dominion customarily used a red primer seal on their commercial cartridges, and may have done so on these rounds as well.