"Did RT Plastics or GGS manufacture WICO chips and did the chips made for the Palms need approval from GCB?"

RT is the manufacturer of the chips.
GGS and Wico were the wholesale and or retailers.

GGS sold out the casino supply to Wico back in early1990's them took it back when WICO went out of business.

Yes for gaming approval for the Palms chips. GGS called in a favor at gaming for the quick approval.