People need to stop thinking that LLMs actually know what they are. They don't. They don't know their Qwen, They don't know they are Opus. They don't even know they are an LLM.
This is why literally every single model's system prompt starts with something like:
"You're Claude Opus a large language model from Anthropic"
They can easily add this "individuality" in RLHF. The base model won't know, correct, but the final user-facing model very much can if that's what they so desire.
I've been browsing Chinese technology site V2EX and have come across various posts claiming similar experiences.