Catalytic converter delete without a tune?

My truck (95 silverado k1500, 5.7 350 ext cab) has only one cat and one pre cat O² sensor.

ChatGPT says that I won't need a tune after a cat delete because there's no post cat O² sensor, and therefore won't throw a check engine light. Is this true? has anyone else done this, and what were the effects, if any?

TYIA!