I have a theory about what TCoRR means:
Technological Consortium Ray Rifle.
The last 2 words are clear, they refer to the Ray Rifle on which this label is present.
What is the Technological Consortium?
As Eric Gurt has referred to the Android's faction as a former company in one of the PB2 Lore Questions it might be the faction who made the Androids. Additionally the Wiki says the Grubs in PB1 were related to TCoRR. This might also explain why they started attacking the human soldiers in the later levels: TCo had activated some backdoors in their programming and taken over control over them. This would also make sense as the Android's attack on the CS was only ours later.
It might also explain why CS isn't using any grubs or Androids: TCo contains every major Android Manufacturer from Earth and they were known to have backdoors + according to Eric Gurt the Androids broke off of Earth some time before the invasion.