What's the point? You can make good or bad software, with or without LLMs. Do you ask a carpenter if they use a hammer or nail gun? Did they only use the nail gun for the roof and the deck?
If you care that much and don't have a foundation of trust, you need to either verify the construction is good, or build it yourself. Anything else is just wishful thinking.
We do ask whether it's handmade or factory.
We even ask when cakes are made in house or frozen even though they look and taste great (at first).
It’s not all-or-nothing: a statement like what I want would be part of the assurance, not the whole thing.